[Bug]: Remote Logins Throws ServiceUnavailable and NotFound Exception thrown In Logs

⚠️ 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 OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

Since upgrading to version 33, our Nextcloud servers logs are full of errors/warnings over and over again. This is happening on multiple servers, including one with 33.0.5. I spent some time clearing the log and debugging and have found it happens when external users log in via either generic link or from the email link we send. All features seem to work, but we are being flooded with messages in our logs. As soon as the remote user connects, we receive 2 entries in the logs:

ServiceUnavailable
Sabre\DAV\Exception\NotFound:

and

NotFound
Exception thrown: Sabre\DAV\Exception\NotFound

More details:

ServiceUnavailable
Sabre\DAV\Exception\NotFound:
/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php
Line 179
OCA\DAV\Connector\Sabre\PublicAuth->check()
/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php
Line 135
Sabre\DAV\Auth\Plugin->check()
/var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php
Line 89
Sabre\DAV\Auth\Plugin->beforeMethod()
/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php
Line 456
Sabre\DAV\Server->emit()
/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php
Line 212
Sabre\DAV\Server->invokeMethod()
/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php
Line 168
OCA\DAV\Connector\Sabre\Server->start()
/var/www/nextcloud/public.php
Line 90
undefinedundefinedrequire_once(
"/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php"
)

and

NotFound
Exception thrown: Sabre\DAV\Exception\NotFound
/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php
Line 126
OCA\DAV\Connector\Sabre\PublicAuth->getToken(
"*** sensitive parameters replaced ***"
)
/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php
Line 82
OCA\DAV\Connector\Sabre\PublicAuth->checkToken()
/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php
Line 179
OCA\DAV\Connector\Sabre\PublicAuth->check()
/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php
Line 135
Sabre\DAV\Auth\Plugin->check()
/var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php
Line 89
Sabre\DAV\Auth\Plugin->beforeMethod()
/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php
Line 456
Sabre\DAV\Server->emit()
/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php
Line 212
Sabre\DAV\Server->invokeMethod()
/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php
Line 168
OCA\DAV\Connector\Sabre\Server->start()
/var/www/nextcloud/public.php
Line 90
undefinedundefinedrequire_once(
"/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php"
)

Steps to reproduce

1. In version 33, share a folder via generic link or email address
2. Connect to the server using either of those links and log in
3. These errors are throw in the logs continually.

Expected behavior

No errors :)

Nextcloud Server version

33

Operating system

RHEL/CentOS

PHP engine version

PHP 8.3

Web server

Apache (supported)

Database engine version

MariaDB

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

None

Are you using the Nextcloud Server Encryption module?

None

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": [
            "btsnc1t"
        ],
        "enabledPreviewProviders": [
            "OC\\Preview\\PNG",
            "OC\\Preview\\JPEG",
            "OC\\Preview\\GIF",
            "OC\\Preview\\HEIC",
            "OC\\Preview\\BMP",
            "OC\\Preview\\XBitmap",
            "OC\\Preview\\MP3",
            "OC\\Preview\\TXT",
            "OC\\Preview\\MarkDown"
        ],
        "default_phone_region": "US",
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "33.0.5.1",
        "overwrite.cli.url": "https:\/\/btsnc1t",
        "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_window_start": 1,
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "25",
        "mail_smtpstreamoptions": {
            "ssl": {
                "allow_self_signed": true,
                "verify_peer": false,
                "verify_peer_name": false
            }
        },
        "memcache.local": "\\OC\\Memcache\\APCu",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "port": 6379,
            "password": "***REMOVED SENSITIVE VALUE***"
        },
        "simpleSignUpLink.shown": false,
        "lost_password_link": "disabled",
        "trashbin_retention_obligation": "auto, 30",
        "ldapProviderFactory": "OCA\\User_LDAP\\LDAPProviderFactory",
        "overwriteprotocol": "https",
        "maintenance": false,
        "loglevel": 2,
        "tempdirectory": "\/ncdata\/tmp",
        "serverid": 99
    }
}

List of activated Apps

Enabled:
  - activity: 6.0.0
  - bruteforcesettings: 6.0.0
  - cloud_federation_api: 1.17.0
  - comments: 1.23.0
  - dav: 1.36.0
  - federatedfilesharing: 1.23.0
  - federation: 1.23.0
  - files: 2.5.0
  - files_accesscontrol: 4.0.1
  - files_automatedtagging: 4.0.0
  - files_downloadlimit: 5.1.0
  - files_external: 1.25.1
  - files_reminders: 1.6.0
  - files_retention: 4.0.1
  - files_sharing: 1.25.2
  - files_trashbin: 1.23.0
  - files_versions: 1.26.0
  - impersonate: 4.0.0
  - logreader: 6.0.0
  - lookup_server_connector: 1.21.0
  - notifications: 6.0.0
  - oauth2: 1.21.0
  - photos: 6.0.0
  - privacy: 5.0.0
  - profile: 1.2.0
  - provisioning_api: 1.23.0
  - related_resources: 4.0.0
  - serverinfo: 5.0.0
  - settings: 1.16.0
  - sharebymail: 1.23.0
  - systemtags: 1.23.0
  - theming: 2.8.0
  - twofactor_backupcodes: 1.22.0
  - twofactor_totp: 15.0.0
  - user_ldap: 1.24.0
  - viewer: 6.0.0
  - webhook_listeners: 1.5.0
  - workflowengine: 2.15.0
Disabled:
  - admin_audit: 1.23.0
  - app_api: 33.0.0 (installed 32.0.0)
  - circles: 33.0.0 (installed 27.0.1)
  - contactsinteraction: 1.14.1 (installed 1.8.0)
  - dashboard: 7.13.0 (installed 7.7.0)
  - encryption: 2.21.0
  - files_pdfviewer: 6.0.0 (installed 2.8.0)
  - firstrunwizard: 6.0.0 (installed 2.16.0)
  - nextcloud_announcements: 5.0.0 (installed 1.16.0)
  - password_policy: 5.0.0 (installed 1.17.0)
  - recommendations: 6.0.0 (installed 1.6.0)
  - support: 5.0.0 (installed 1.10.0)
  - survey_client: 5.0.0 (installed 1.15.0)
  - suspicious_login: 11.0.0
  - testing: 1.23.0
  - text: 7.0.1 (installed 3.8.0)
  - twofactor_nextcloud_notification: 7.0.0
  - updatenotification: 1.23.0 (installed 1.17.0)
  - user_status: 1.13.0 (installed 1.7.0)
  - weather_status: 1.13.0 (installed 1.7.0)

Nextcloud Signing status

Nextcloud Logs

{"reqId":"aiAkVVbhw0db6tfQEbk02wAAAIo","level":3,"time":"2026-06-03T12:55:49+00:00","remoteAddr":"10.35.108.36","user":"--","app":"no app in context","method":"PROPFIND","url":"/nextcloud/public.php/dav/systemtags/","scriptName":"/nextcloud/public.php","message":"Exception thrown: Sabre\\DAV\\Exception\\NotFound","userAgent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36","version":"33.0.5.1","exception":{"Exception":"Sabre\\DAV\\Exception\\NotFound","Message":"","Code":0,"Trace":[{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php","line":126,"function":"getToken","class":"OCA\\DAV\\Connector\\Sabre\\PublicAuth","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php","line":82,"function":"checkToken","class":"OCA\\DAV\\Connector\\Sabre\\PublicAuth","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php","line":179,"function":"check","class":"OCA\\DAV\\Connector\\Sabre\\PublicAuth","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php","line":135,"function":"check","class":"Sabre\\DAV\\Auth\\Plugin","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php","line":89,"function":"beforeMethod","class":"Sabre\\DAV\\Auth\\Plugin","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":456,"function":"emit","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php","line":212,"function":"invokeMethod","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php","line":168,"function":"start","class":"OCA\\DAV\\Connector\\Sabre\\Server","type":"->"},{"file":"/var/www/nextcloud/public.php","line":90,"args":["/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php"],"function":"require_once"}],"File":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php","Line":113,"message":"","exception":"{\"class\":\"Sabre\\DAV\\Exception\\NotFound\",\"message\":\"\",\"code\":0,\"file\":\"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php:113\",\"trace\":\"#0 /var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php(126): OCA\\DAV\\Connector\\Sabre\\PublicAuth->getToken()\\n#1 /var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php(82): OCA\\DAV\\Connector\\Sabre\\PublicAuth->checkToken()\\n#2 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php(179): OCA\\DAV\\Connector\\Sabre\\PublicAuth->check()\\n#3 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php(135): Sabre\\DAV\\Auth\\Plugin->check()\\n#4 /var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php(89): Sabre\\DAV\\Auth\\Plugin->beforeMethod()\\n#5 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php(456): Sabre\\DAV\\Server->emit()\\n#6 /var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php(212): Sabre\\DAV\\Server->invokeMethod()\\n#7 /var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php(168): OCA\\DAV\\Connector\\Sabre\\Server->start()\\n#8 /var/www/nextcloud/public.php(90): require_once('...')\\n#9 {main}\"}","CustomMessage":"Exception thrown: Sabre\\DAV\\Exception\\NotFound"}}
{"reqId":"aiAkVVbhw0db6tfQEbk02wAAAIo","level":3,"time":"2026-06-03T12:55:49+00:00","remoteAddr":"10.35.108.36","user":"--","app":"webdav","method":"PROPFIND","url":"/nextcloud/public.php/dav/systemtags/","scriptName":"/nextcloud/public.php","message":"Sabre\\DAV\\Exception\\NotFound: ","userAgent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36","version":"33.0.5.1","exception":{"Exception":"Sabre\\DAV\\Exception\\ServiceUnavailable","Message":"Sabre\\DAV\\Exception\\NotFound: ","Code":0,"Trace":[{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php","line":179,"function":"check","class":"OCA\\DAV\\Connector\\Sabre\\PublicAuth","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php","line":135,"function":"check","class":"Sabre\\DAV\\Auth\\Plugin","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php","line":89,"function":"beforeMethod","class":"Sabre\\DAV\\Auth\\Plugin","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":456,"function":"emit","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php","line":212,"function":"invokeMethod","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php","line":168,"function":"start","class":"OCA\\DAV\\Connector\\Sabre\\Server","type":"->"},{"file":"/var/www/nextcloud/public.php","line":90,"args":["/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php"],"function":"require_once"}],"File":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php","Line":99,"message":"Sabre\\DAV\\Exception\\NotFound: ","exception":"{\"class\":\"Sabre\\DAV\\Exception\\ServiceUnavailable\",\"message\":\"Sabre\\DAV\\Exception\\NotFound: \",\"code\":0,\"file\":\"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php:99\",\"trace\":\"#0 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php(179): OCA\\DAV\\Connector\\Sabre\\PublicAuth->check()\\n#1 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php(135): Sabre\\DAV\\Auth\\Plugin->check()\\n#2 /var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php(89): Sabre\\DAV\\Auth\\Plugin->beforeMethod()\\n#3 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php(456): Sabre\\DAV\\Server->emit()\\n#4 /var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php(212): Sabre\\DAV\\Server->invokeMethod()\\n#5 /var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php(168): OCA\\DAV\\Connector\\Sabre\\Server->start()\\n#6 /var/www/nextcloud/public.php(90): require_once('...')\\n#7 {main}\"}","CustomMessage":"Sabre\\DAV\\Exception\\NotFound: "}}
{"reqId":"aiAkVoI_JHjtZMueO7D9IAAAAM4","level":3,"time":"2026-06-03T12:55:50+00:00","remoteAddr":"10.35.108.36","user":"--","app":"no app in context","method":"PROPFIND","url":"/nextcloud/public.php/dav/systemtags/","scriptName":"/nextcloud/public.php","message":"Exception thrown: Sabre\\DAV\\Exception\\NotFound","userAgent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36","version":"33.0.5.1","exception":{"Exception":"Sabre\\DAV\\Exception\\NotFound","Message":"","Code":0,"Trace":[{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php","line":126,"function":"getToken","class":"OCA\\DAV\\Connector\\Sabre\\PublicAuth","type":"->","args":["*** sensitive parameters replaced ***"]},{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php","line":82,"function":"checkToken","class":"OCA\\DAV\\Connector\\Sabre\\PublicAuth","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php","line":179,"function":"check","class":"OCA\\DAV\\Connector\\Sabre\\PublicAuth","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php","line":135,"function":"check","class":"Sabre\\DAV\\Auth\\Plugin","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php","line":89,"function":"beforeMethod","class":"Sabre\\DAV\\Auth\\Plugin","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":456,"function":"emit","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php","line":212,"function":"invokeMethod","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php","line":168,"function":"start","class":"OCA\\DAV\\Connector\\Sabre\\Server","type":"->"},{"file":"/var/www/nextcloud/public.php","line":90,"args":["/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php"],"function":"require_once"}],"File":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php","Line":113,"message":"","exception":"{\"class\":\"Sabre\\DAV\\Exception\\NotFound\",\"message\":\"\",\"code\":0,\"file\":\"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php:113\",\"trace\":\"#0 /var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php(126): OCA\\DAV\\Connector\\Sabre\\PublicAuth->getToken()\\n#1 /var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php(82): OCA\\DAV\\Connector\\Sabre\\PublicAuth->checkToken()\\n#2 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php(179): OCA\\DAV\\Connector\\Sabre\\PublicAuth->check()\\n#3 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php(135): Sabre\\DAV\\Auth\\Plugin->check()\\n#4 /var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php(89): Sabre\\DAV\\Auth\\Plugin->beforeMethod()\\n#5 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php(456): Sabre\\DAV\\Server->emit()\\n#6 /var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php(212): Sabre\\DAV\\Server->invokeMethod()\\n#7 /var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php(168): OCA\\DAV\\Connector\\Sabre\\Server->start()\\n#8 /var/www/nextcloud/public.php(90): require_once('...')\\n#9 {main}\"}","CustomMessage":"Exception thrown: Sabre\\DAV\\Exception\\NotFound"}}
{"reqId":"aiAkVoI_JHjtZMueO7D9IAAAAM4","level":3,"time":"2026-06-03T12:55:50+00:00","remoteAddr":"10.35.108.36","user":"--","app":"webdav","method":"PROPFIND","url":"/nextcloud/public.php/dav/systemtags/","scriptName":"/nextcloud/public.php","message":"Sabre\\DAV\\Exception\\NotFound: ","userAgent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36","version":"33.0.5.1","exception":{"Exception":"Sabre\\DAV\\Exception\\ServiceUnavailable","Message":"Sabre\\DAV\\Exception\\NotFound: ","Code":0,"Trace":[{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php","line":179,"function":"check","class":"OCA\\DAV\\Connector\\Sabre\\PublicAuth","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php","line":135,"function":"check","class":"Sabre\\DAV\\Auth\\Plugin","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php","line":89,"function":"beforeMethod","class":"Sabre\\DAV\\Auth\\Plugin","type":"->"},{"file":"/var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php","line":456,"function":"emit","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php","line":212,"function":"invokeMethod","class":"Sabre\\DAV\\Server","type":"->"},{"file":"/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php","line":168,"function":"start","class":"OCA\\DAV\\Connector\\Sabre\\Server","type":"->"},{"file":"/var/www/nextcloud/public.php","line":90,"args":["/var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php"],"function":"require_once"}],"File":"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php","Line":99,"message":"Sabre\\DAV\\Exception\\NotFound: ","exception":"{\"class\":\"Sabre\\DAV\\Exception\\ServiceUnavailable\",\"message\":\"Sabre\\DAV\\Exception\\NotFound: \",\"code\":0,\"file\":\"/var/www/nextcloud/apps/dav/lib/Connector/Sabre/PublicAuth.php:99\",\"trace\":\"#0 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php(179): OCA\\DAV\\Connector\\Sabre\\PublicAuth->check()\\n#1 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Auth/Plugin.php(135): Sabre\\DAV\\Auth\\Plugin->check()\\n#2 /var/www/nextcloud/3rdparty/sabre/event/lib/WildcardEmitterTrait.php(89): Sabre\\DAV\\Auth\\Plugin->beforeMethod()\\n#3 /var/www/nextcloud/3rdparty/sabre/dav/lib/DAV/Server.php(456): Sabre\\DAV\\Server->emit()\\n#4 /var/www/nextcloud/apps/dav/lib/Connector/Sabre/Server.php(212): Sabre\\DAV\\Server->invokeMethod()\\n#5 /var/www/nextcloud/apps/dav/appinfo/v2/publicremote.php(168): OCA\\DAV\\Connector\\Sabre\\Server->start()\\n#6 /var/www/nextcloud/public.php(90): require_once('...')\\n#7 {main}\"}","CustomMessage":"Sabre\\DAV\\Exception\\NotFound: "}}

Additional info

No response

Start with apps/dav/lib/Connector/Sabre/PublicAuth.php, especially getToken(), checkToken(), and check(), then follow the request entry point in apps/dav/appinfo/v2/publicremote.php. Reproduce a remote login through a generic or emailed share link and inspect the resulting DAV logs. Done means these log errors no longer occur while remote access continues to work.