[Bug]: Sharing to a federated group returns an error on Web.

⚠️ 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

The request:

{
  "path": "/Shared/blak",
  "permissions": 31,
  "shareType": 9,
  "shareWith": "tos@xxxx.nextcloud.com",
  "expireDate": "",
  "attributes": "[{\"value\":true,\"key\":\"download\",\"scope\":\"permissions\"}]"
}

Response:

{
  "ocs": {
    "meta": {
      "status": "failure",
      "statuscode": 403,
      "message": "Failed to create share."
    },
    "data": []
  }
}

Steps to reproduce

1. Be on Web
2. Share to federated group
3. Get error

Expected behavior

No error, and share should be created.

Nextcloud Server version

30

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

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

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

Additional info

No response

No source file, test, or code entry point is named. Start by reproducing the Web request for sharing to a federated group and inspect the resulting 403 and server logs; done means the share is created without the error.