$ touch /home/yunohost.app/nextcloud/data/.ocdata
$ php --define apc.enable_cli=1 /var/www/nextcloud/occ --no-ansi app:list --output json
{"enabled":{"activity":"2.21.1","calendar":"4.7.19","circles":"29.0.0-dev","cloud_federation_api":"1.12.0","comments":"1.19.0","contacts":"6.0.6","contactsinteraction":"1.10.0","cookbook":"0.11.4","dashboard":"7.9.0","dav":"1.30.1","deck":"1.13.6","drawio":"3.0.9","federatedfilesharing":"1.19.0","federation":"1.19.0","files":"2.1.1","files_downloadlimit":"2.0.0","files_external":"1.21.0","files_pdfviewer":"2.10.0","files_reminders":"1.2.0","files_sharing":"1.21.0","files_trashbin":"1.19.0","files_versions":"1.22.0","firstrunwizard":"2.18.0","flow_notifications":"1.9.0","logreader":"2.14.0","lookup_server_connector":"1.17.0","mail":"3.7.24","metadata":"0.22.0","music":"2.4.0","nextcloud_announcements":"1.18.0","notes":"4.12.3","notifications":"2.17.0","notify_push":"1.2.0","oauth2":"1.17.1","password_policy":"1.19.0","photos":"2.5.0","privacy":"1.13.0","provisioning_api":"1.19.0","recommendations":"2.1.0","related_resources":"1.4.0","serverinfo":"1.19.0","settings":"1.12.0","sharebymail":"1.19.0","support":"1.12.0","survey_client":"1.17.0","systemtags":"1.19.0","tasks":"0.16.1","text":"3.10.1","theming":"2.4.0","twofactor_backupcodes":"1.18.0","user_ldap":"1.20.0","user_status":"1.9.0","viewer":"2.3.0","weather_status":"1.9.0","workflow_script":"1.14.1","workflowengine":"2.11.0"},"disabled":{"accessibility":"1.10.0","admin_audit":"1.19.0","breezedark":"29.0.0 (installed 29.0.0)","bruteforcesettings":"2.9.0","encryption":"2.17.0 (installed 2.17.0)","files_rightclick":"1.6.0 (installed 1.6.0)","files_videoplayer":"1.13.0","news":"25.3.1 (installed 25.3.1)","spreed":"19.0.15 (installed 19.0.15)","suspicious_login":"7.0.0","talk_matterbridge":"1.31.1026000 (installed 1.31.1026000)","twofactor_totp":"11.0.0-dev","updatenotification":"1.19.1 (installed 1.14.0)"}}
Nextcloud homepage becomes :
Internal Server Error
The server encountered an internal error and was unable to complete your request.
Please contact the server administrator if this error reappears multiple times, please include the technical details below in your report.
More details can be found in the server log.
Tried to do an update and got : https://paste.yunohost.org/raw/gihepeqova
(And back to square 1 for nextcloud in maintenance mode.)
So I suppose that being able to de-activate the mail app and try again, maybe this will work?