Connection Wizard is stalled at “Grant access”

I tried to install Nextcloud app on iOS and when I click on “Grant access”, it doe not go forward - it is just stalled there.

Nextcloud is installed on Ubuntu server as snap, and in /var/snap/nextcloud/current/nextcloud/config/config.php I have this:

 'trusted_domains' => 
  array (
    0 => '',
    1 => '',
  'datadirectory' => '/var/snap/nextcloud/common/nextcloud/data',
  'dbtype' => 'mysql',
  'version' => '',
  'overwrite.cli.url' => '',
  'overwriteprotocol' => 'https',

As I understood, 'overwriteprotocol' => 'https', is the solution, but I already had this and it is still not working… any help?