Setup

• MediaWiki 1.35.5 (5ffae99) 21:10, 10. Jan. 2022
• PHP 7.4.3 (apache2handler)
• MariaDB 10.3.32-MariaDB-0ubuntu0.20.04.1
• GoogleLogin 0.4.0-git (6be3b26) 06:57, 24. Jan. 2022

Issue
"update.php" was run after enabling as well as "updatePublicSuffixArray.php".

$wgGLAllowedDomainsDB = true;
$wgGroupPermissions['sysop']['managegooglelogindomains'] = true;

It is possible to add a first domain however on "Special:GoogleLoginAllowedDomains" there is no way to tell which domain it was since the saved domain is not readable. See attached screenshot.

When trying to add a second domain if fails with "When changing the list of permissive domains an error occurred" (my translation of Beim Ändern der Liste der erlaubten Domains ist ein Fehler aufgetreten.)

In any case nobody can log into the wiki. A stacktrace is not emitted.