Unable to update app «Collabora Online»

  • Goto Apps > Your Apps
  • Locate «Collabora Online - Built-in CODE Server»
  • Click the Button [Update to 22.5.702]
  • After 2-3 seconds there is an error message «An error occurred during the request. Unable to proceed.»

No further actions are possible since there is a message «Maintenance mode».
I need to open config.php and change
‘maintenance’ => true,
to
‘maintenance’ => false,

Then Nextcloud is accessible again, but the app is not updateable.

[Nextcloud Hub 3] (25.0.1)