Unable to update recovery keys (user-key encryption)

Hi guys,
I have an ownCloud instance on my server with user-key encryption enabled.
Today I was trying to enable or disable password recovery but I have no luck…
When I select an option with it says “Updating recovery keys. This can take some time…” and it goes forever.

(The problem does not occur if the user has few files or if he has no files)

Steps to reproduce

  1. Go to the user settings
  2. Select the encryption tab
  3. Enable or disable the password recovery functionality

Expected behaviour

Process should terminate with success

Actual behaviour

Process takes forever and does not terminate

Server configuration

Operating system: Ubuntu 20.04

Web server: Apache

Database: MySQL

PHP version: 7.3

ownCloud version: 10.7

Updated from an older ownCloud or fresh install: updated

Where did you install ownCloud from: tarball

Login as admin user into your ownCloud and access 
http://example.com/index.php/settings/integrity/failed 
paste the results into https://gist.github.com/ and puth the link here.

(Small file, I copy it here)

Results
=======
- user
	- EXCEPTION
		- OC\IntegrityCheck\Exceptions\MissingSignatureException
		- Signature data not found.

Raw output
==========
Array
(
    [user] => Array
        (
            [EXCEPTION] => Array
                (
                    [class] => OC\IntegrityCheck\Exceptions\MissingSignatureException
                    [message] => Signature data not found.
                )

        )

)

The content of config/config.php:

{
    "system": {
        "instanceid": "ocgzvz7g2f1q",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "***REMOVED SENSITIVE VALUE***"
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "overwrite.cli.url": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "10.7.0.4",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "logtimezone": "UTC",
        "installed": true,
        "loglevel": 3,
        "singleuser": false,
        "maintenance": false,
        "theme": "",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_smtpauth": 1,
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpsecure": "ssl",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "enable_previews": true,
        "preview_max_x": 1000,
        "preview_max_y": 1000,
        "preview_max_scale_factor": 1,
        "trashbin_retention_obligation": 30,
        "filelocking.enabled": false,
        "has_rebuilt_cache": true
    }
}

List of activated apps:

Enabled:
  - brute_force_protection:
    - Version: 1.1.0
  - calendar:
    - Version: 1.6.4
  - camerarawpreviews:
    - Version: 0.7.11
  - checksum:
    - Version: 0.3.5
  - configreport:
    - Version: 0.2.0
  - contacts:
    - Version: 1.5.5
  - dav:
    - Version: 0.6.0
  - drawio:
    - Version: 0.0.9
  - encryption:
    - Version: 1.5.0
  - federatedfilesharing:
    - Version: 0.5.0
  - files:
    - Version: 1.5.2
  - files_clipboard:
    - Version: 1.0.3
  - files_external:
    - Version: 0.7.1
  - files_mediaviewer:
    - Version: 1.0.4
  - files_pdfviewer:
    - Version: 0.12.1
  - files_sharing:
    - Version: 0.14.0
  - files_texteditor:
    - Version: 2.3.1
  - files_textviewer:
    - Version: 1.0.3
  - files_trashbin:
    - Version: 0.9.1
  - files_versions:
    - Version: 1.3.0
  - gallery:
    - Version: 16.1.1
  - impersonate:
    - Version: 0.5.0
  - market:
    - Version: 0.6.0
  - metadata:
    - Version: 0.10.0
  - music:
    - Version: 1.2.0
  - provisioning_api:
    - Version: 0.5.0
  - szfs:
    - Version: 1.0.0
  - tasks:
    - Version: 0.9.7
  - templateeditor:
    - Version: 0.4.0
  - twofactor_totp:
    - Version: 0.7.1
  - updatenotification:
    - Version: 0.2.1

Are you using external storage, if yes which one: no

Are you using encryption: yes

Are you using an external user-backend, if yes which one: no

Client configuration

Browser: Google Chrome 91.0.4472.114

Operating system: macOS 11.4

Logs

Web server error log

[Sat Jul 10 09:57:05.940692 2021] [proxy_fcgi:error] [pid 241042:tid 139941535262464] (70007)The timeout specified has expired: [client 37.160.9.3:8675] AH01075: Error dispatching request to : (polling)

ownCloud log (data/owncloud.log)

no log triggered