[Bug]: Federating (sharing files to remote) fails with "File not found" for instances on the same server

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• Nextcloud Server is running on 64bit capable CPU, PHP and OS.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

I have set up two Nextcloud servers on different domains and want to share files between them. I have been able to add them to each other's trusted servers (though remain yellow). When sharing to either a remote user or group, the remote user is notified. When opening the 'share' on the remote server, the

Steps to reproduce

1. From Server B share a file to a remote Server A
2. Receive file on Server A
3. See error

Expected behavior

File opens

Installation method

Community Web installer on a VPS or web space

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.0

Web server

Apache (supported)

Database engine version

MySQL

Is this bug present after an update or on a fresh install?

Fresh Nextcloud Server install

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "cloud.****REDACTED ENTRY****"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "25.0.2.3",
        "overwrite.cli.url": "https:\/\/cloud.****REDACTED ENTRY****",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "maintenance": false,
        "htaccess.RewriteBase": "\/",
        "htaccess.IgnoreFrontController": true
    }
}

List of activated Apps

Enabled:
  - activity: 2.17.0
  - bookmarks: 12.0.0
  - bruteforcesettings: 2.5.0
  - calendar: 4.2.1
  - circles: 25.0.0
  - cloud_federation_api: 1.8.0
  - contacts: 5.0.2
  - contactsinteraction: 1.6.0
  - dav: 1.24.0
  - federatedfilesharing: 1.15.0
  - federation: 1.15.0
  - files: 1.20.1
  - files_markdown: 2.3.6
  - files_mindmap: 0.0.27
  - files_pdfviewer: 2.6.0
  - files_rightclick: 1.4.0
  - files_sharing: 1.17.0
  - files_texteditor: 2.15.0
  - files_trashbin: 1.15.0
  - files_versions: 1.18.0
  - fileslibreofficeedit: 1.1.0
  - integration_onedrive: 1.1.4
  - logreader: 2.10.0
  - lookup_server_connector: 1.13.0
  - mail: 2.2.2
  - notes: 4.6.0
  - notifications: 2.13.1
  - oauth2: 1.13.0
  - oidc: 0.2.8
  - password_policy: 1.15.0
  - photos: 2.0.1
  - privacy: 1.9.0
  - provisioning_api: 1.15.0
  - recommendations: 1.4.0
  - related_resources: 1.0.3
  - settings: 1.7.0
  - sharebymail: 1.15.0
  - social: 0.5.0-beta3
  - spreed: 15.0.2
  - survey_client: 1.13.0
  - suspicious_login: 4.3.0
  - systemtags: 1.15.0
  - tasks: 0.14.5
  - text: 3.6.0
  - theming: 2.0.1
  - twofactor_backupcodes: 1.14.0
  - twofactor_totp: 7.0.0
  - updatenotification: 1.15.0
  - user_status: 1.5.0
  - viewer: 1.9.0
  - weather_status: 1.5.0
  - workflowengine: 2.7.0
Disabled:
  - admin_audit: 1.15.0
  - comments: 1.15.0
  - dashboard: 7.5.0
  - deck: 1.8.3
  - encryption
  - external: 5.0.0
  - externalportal: 1.0.2
  - files_external
  - firstrunwizard: 2.14.0
  - integration_discourse: 1.0.4
  - integration_github: 1.0.14
  - integration_gitlab: 1.0.12
  - integration_mastodon: 1.0.3
  - nextcloud_announcements: 1.14.0
  - serverinfo: 1.15.0
  - support: 1.8.0
  - user_ldap

Nextcloud Signing status

Hasn't failed

Nextcloud Logs

{"reqId":"Y74@4lsiDhy0hTwh3rVfNQAAAAM","level":2,"time":"2023-01-11T04:45:22+00:00","remoteAddr":"***REDACTED***","user":"gbraad","app":"no app in context","method":"PROPFIND","url":"/remote.php/dav/files/gbraad/","message":"External storage not available: Sabre\\HTTP\\ClientHttpException: Internal Server Error","userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36","version":"25.0.2.3","exception":{"Exception":"OCP\\Files\\StorageNotAvailableException","Message":"Sabre\\HTTP\\ClientHttpException: Internal Server Error","Code":1,"Trace":[{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/DAV.php","line":287,"function":"convertException","class":"OC\\Files\\Storage\\DAV","type":"->","args":[{"__class__":"Sabre\\HTTP\\ClientHttpException"},""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/DAV.php","line":584,"function":"propfind","class":"OC\\Files\\Storage\\DAV","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Common.php","line":462,"function":"stat","class":"OC\\Files\\Storage\\DAV","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/files_sharing/lib/External/Storage.php","line":195,"function":"test","class":"OC\\Files\\Storage\\Common","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Wrapper.php","line":474,"function":"test","class":"OCA\\Files_Sharing\\External\\Storage","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Availability.php","line":69,"function":"test","class":"OC\\Files\\Storage\\Wrapper\\Wrapper","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Availability.php","line":83,"function":"updateAvailability","class":"OC\\Files\\Storage\\Wrapper\\Availability","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Availability.php","line":92,"function":"isAvailable","class":"OC\\Files\\Storage\\Wrapper\\Availability","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Availability.php","line":445,"function":"checkAvailability","class":"OC\\Files\\Storage\\Wrapper\\Availability","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Wrapper.php","line":599,"function":"getMetaData","class":"OC\\Files\\Storage\\Wrapper\\Availability","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Cache/Scanner.php","line":116,"function":"getMetaData","class":"OC\\Files\\Storage\\Wrapper\\Wrapper","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Cache/Scanner.php","line":154,"function":"getData","class":"OC\\Files\\Cache\\Scanner","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/files_sharing/lib/External/Scanner.php","line":57,"function":"scanFile","class":"OC\\Files\\Cache\\Scanner","type":"->","args":["",0,-1,null,true,null]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/View.php","line":1502,"function":"scanFile","class":"OCA\\Files_Sharing\\External\\Scanner","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Node/Folder.php","line":101,"function":"getDirectoryContent","class":"OC\\Files\\View","type":"->","args":["/","",{"__class__":"OC\\Files\\Node\\LazyUserFolder"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Share20/DefaultShareProvider.php","line":697,"function":"getDirectoryListing","class":"OC\\Files\\Node\\Folder","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Share20/Manager.php","line":1311,"function":"getSharesInFolder","class":"OC\\Share20\\DefaultShareProvider","type":"->","args":["gbraad",{"__class__":"OC\\Files\\Node\\Folder"},true,true]},{"function":"OC\\Share20\\{closure}","class":"OC\\Share20\\Manager","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Share20/Manager.php","line":1320,"function":"array_reduce","args":[["*** sensitive parameters replaced ***",{"__class__":"OCA\\FederatedFileSharing\\FederatedShareProvider"},{"__class__":"OCA\\ShareByMail\\ShareByMailProvider"},{"__class__":"OCA\\Circles\\ShareByCircleProvider"},{"__class__":"OCA\\Talk\\Share\\RoomShareProvider"}],{"__class__":"Closure"},"*** sensitive parameters replaced ***"]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/lib/Connector/Sabre/SharesPlugin.php","line":137,"function":"getSharesInFolder","class":"OC\\Share20\\Manager","type":"->","args":["gbraad",{"__class__":"OC\\Files\\Node\\Folder"},true]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/lib/Connector/Sabre/SharesPlugin.php","line":194,"function":"getSharesFolder","class":"OCA\\DAV\\Connector\\Sabre\\SharesPlugin","type":"->","args":[{"__class__":"OC\\Files\\Node\\Folder"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php","line":89,"function":"handleGetProperties","class":"OCA\\DAV\\Connector\\Sabre\\SharesPlugin","type":"->","args":[{"__class__":"Sabre\\DAV\\PropFind"},{"__class__":"OCA\\DAV\\Files\\FilesHome"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":1052,"function":"emit","class":"Sabre\\DAV\\Server","type":"->","args":["propFind",[{"__class__":"Sabre\\DAV\\PropFind"},{"__class__":"OCA\\DAV\\Files\\FilesHome"}]]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":984,"function":"getPropertiesByNode","class":"Sabre\\DAV\\Server","type":"->","args":[{"__class__":"Sabre\\DAV\\PropFind"},{"__class__":"OCA\\DAV\\Files\\FilesHome"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":1662,"function":"getPropertiesIteratorForPath","class":"Sabre\\DAV\\Server","type":"->","args":["files/gbraad",["{DAV:}getlastmodified","{DAV:}getetag","{DAV:}getcontenttype","{DAV:}resourcetype","{http://owncloud.org/ns}fileid","And 14 more entries, set log level to debug to see all entries"],1]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":1647,"function":"writeMultiStatus","class":"Sabre\\DAV\\Server","type":"->","args":[{"__class__":"Sabre\\Xml\\Writer","elementMap":[],"contextUri":"/remote.php/dav/","namespaceMap":{"DAV:":"d","http://sabredav.org/ns":"s","http://owncloud.org/ns":"oc","http://nextcloud.org/ns":"nc"},"classMap":[]},{"__class__":"Generator"},false]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/CorePlugin.php","line":346,"function":"generateMultiStatus","class":"Sabre\\DAV\\Server","type":"->","args":[{"__class__":"Generator"},false]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php","line":89,"function":"httpPropFind","class":"Sabre\\DAV\\CorePlugin","type":"->","args":[{"__class__":"Sabre\\HTTP\\Request"},{"__class__":"Sabre\\HTTP\\Response"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":472,"function":"emit","class":"Sabre\\DAV\\Server","type":"->","args":["method:PROPFIND",[{"__class__":"Sabre\\HTTP\\Request"},{"__class__":"Sabre\\HTTP\\Response"}]]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":253,"function":"invokeMethod","class":"Sabre\\DAV\\Server","type":"->","args":[{"__class__":"Sabre\\HTTP\\Request"},{"__class__":"Sabre\\HTTP\\Response"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":321,"function":"start","class":"Sabre\\DAV\\Server","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/lib/Server.php","line":360,"function":"exec","class":"Sabre\\DAV\\Server","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/appinfo/v2/remote.php","line":35,"function":"exec","class":"OCA\\DAV\\Server","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/remote.php","line":171,"args":["/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/appinfo/v2/remote.php"],"function":"require_once"}],"File":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/DAV.php","Line":860,"Hint":"Storage is temporarily not available","message":"External storage not available: Sabre\\HTTP\\ClientHttpException: Internal Server Error","exception":{},"CustomMessage":"External storage not available: Sabre\\HTTP\\ClientHttpException: Internal Server Error"}}
{"reqId":"Y74@4lsiDhy0hTwh3rVfNQAAAAM","level":2,"time":"2023-01-11T04:45:23+00:00","remoteAddr":"***REDACTED***","user":"gbraad","app":"no app in context","method":"PROPFIND","url":"/remote.php/dav/files/gbraad/","message":"External storage not available: Sabre\\HTTP\\ClientHttpException: Internal Server Error","userAgent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36","version":"25.0.2.3","exception":{"Exception":"OCP\\Files\\StorageNotAvailableException","Message":"Sabre\\HTTP\\ClientHttpException: Internal Server Error","Code":1,"Trace":[{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/DAV.php","line":287,"function":"convertException","class":"OC\\Files\\Storage\\DAV","type":"->","args":[{"__class__":"Sabre\\HTTP\\ClientHttpException"},""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/DAV.php","line":584,"function":"propfind","class":"OC\\Files\\Storage\\DAV","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Common.php","line":462,"function":"stat","class":"OC\\Files\\Storage\\DAV","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/files_sharing/lib/External/Storage.php","line":195,"function":"test","class":"OC\\Files\\Storage\\Common","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Wrapper.php","line":474,"function":"test","class":"OCA\\Files_Sharing\\External\\Storage","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Availability.php","line":69,"function":"test","class":"OC\\Files\\Storage\\Wrapper\\Wrapper","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Availability.php","line":83,"function":"updateAvailability","class":"OC\\Files\\Storage\\Wrapper\\Availability","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Availability.php","line":92,"function":"isAvailable","class":"OC\\Files\\Storage\\Wrapper\\Availability","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Availability.php","line":445,"function":"checkAvailability","class":"OC\\Files\\Storage\\Wrapper\\Availability","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/Wrapper/Wrapper.php","line":599,"function":"getMetaData","class":"OC\\Files\\Storage\\Wrapper\\Availability","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Cache/Scanner.php","line":116,"function":"getMetaData","class":"OC\\Files\\Storage\\Wrapper\\Wrapper","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Cache/Scanner.php","line":154,"function":"getData","class":"OC\\Files\\Cache\\Scanner","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/files_sharing/lib/External/Scanner.php","line":57,"function":"scanFile","class":"OC\\Files\\Cache\\Scanner","type":"->","args":["",0,-1,null,true,null]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/View.php","line":1502,"function":"scanFile","class":"OCA\\Files_Sharing\\External\\Scanner","type":"->","args":[""]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Node/Folder.php","line":101,"function":"getDirectoryContent","class":"OC\\Files\\View","type":"->","args":["/","",{"__class__":"OC\\Files\\Node\\LazyUserFolder"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/lib/Connector/Sabre/Directory.php","line":260,"function":"getDirectoryListing","class":"OC\\Files\\Node\\Folder","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/lib/Connector/Sabre/TagsPlugin.php","line":227,"function":"getChildren","class":"OCA\\DAV\\Connector\\Sabre\\Directory","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php","line":89,"function":"handleGetProperties","class":"OCA\\DAV\\Connector\\Sabre\\TagsPlugin","type":"->","args":[{"__class__":"Sabre\\DAV\\PropFind"},{"__class__":"OCA\\DAV\\Files\\FilesHome"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":1052,"function":"emit","class":"Sabre\\DAV\\Server","type":"->","args":["propFind",[{"__class__":"Sabre\\DAV\\PropFind"},{"__class__":"OCA\\DAV\\Files\\FilesHome"}]]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":984,"function":"getPropertiesByNode","class":"Sabre\\DAV\\Server","type":"->","args":[{"__class__":"Sabre\\DAV\\PropFind"},{"__class__":"OCA\\DAV\\Files\\FilesHome"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":1662,"function":"getPropertiesIteratorForPath","class":"Sabre\\DAV\\Server","type":"->","args":["files/gbraad",["{DAV:}getlastmodified","{DAV:}getetag","{DAV:}getcontenttype","{DAV:}resourcetype","{http://owncloud.org/ns}fileid","And 14 more entries, set log level to debug to see all entries"],1]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":1647,"function":"writeMultiStatus","class":"Sabre\\DAV\\Server","type":"->","args":[{"__class__":"Sabre\\Xml\\Writer","elementMap":[],"contextUri":"/remote.php/dav/","namespaceMap":{"DAV:":"d","http://sabredav.org/ns":"s","http://owncloud.org/ns":"oc","http://nextcloud.org/ns":"nc"},"classMap":[]},{"__class__":"Generator"},false]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/CorePlugin.php","line":346,"function":"generateMultiStatus","class":"Sabre\\DAV\\Server","type":"->","args":[{"__class__":"Generator"},false]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php","line":89,"function":"httpPropFind","class":"Sabre\\DAV\\CorePlugin","type":"->","args":[{"__class__":"Sabre\\HTTP\\Request"},{"__class__":"Sabre\\HTTP\\Response"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":472,"function":"emit","class":"Sabre\\DAV\\Server","type":"->","args":["method:PROPFIND",[{"__class__":"Sabre\\HTTP\\Request"},{"__class__":"Sabre\\HTTP\\Response"}]]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":253,"function":"invokeMethod","class":"Sabre\\DAV\\Server","type":"->","args":[{"__class__":"Sabre\\HTTP\\Request"},{"__class__":"Sabre\\HTTP\\Response"}]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":321,"function":"start","class":"Sabre\\DAV\\Server","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/lib/Server.php","line":360,"function":"exec","class":"Sabre\\DAV\\Server","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/appinfo/v2/remote.php","line":35,"function":"exec","class":"OCA\\DAV\\Server","type":"->","args":[]},{"file":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/remote.php","line":171,"args":["/home/spotsnel_gbraad/sites/****REDACTED****/cloud/apps/dav/appinfo/v2/remote.php"],"function":"require_once"}],"File":"/home/spotsnel_gbraad/sites/****REDACTED****/cloud/lib/private/Files/Storage/DAV.php","Line":860,"Hint":"Storage is temporarily not available","message":"External storage not available: Sabre\\HTTP\\ClientHttpException: Internal Server Error","exception":{},"CustomMessage":"External storage not available: Sabre\\HTTP\\ClientHttpException: Internal Server Error"}}

Additional info

Initiated remote from Server B to Server A:

File shows up in 'shares' on Server A:

Error as shown on Server A:

Note: this issue occurs both ways. Servers are identically configured.

Read apps/files_sharing/lib/External/Storage.php and lib/private/Files/Storage/DAV.php, following the logged call from External\Storage::test through DAV::propfind. Reproduce the federation flow between the two servers and trace why the remote file is reported as unavailable; done means the shared file opens on Server A without the logged storage error.