ERROR Piwik\FrontController Uncaught exception: Error:
Call to undefined method Piwik\Plugins\Login\Auth::setForceLogin()
in /srv/www/matomo/plugins/LoginOIDC/Controller.php:431
It seems it loaded the methods from Piwik\Auth instead of Piwik\Plugins\LoginOIDC\OIDCAuth - which worked for getLogin() (which exists in both files), but failed at setForceLogin() (which only exists in the latter).
Resolve:
It seems it loaded the methods from Piwik\Auth instead of Piwik\Plugins\LoginOIDC\OIDCAuth - which worked for getLogin() (which exists in both files), but failed at setForceLogin() (which only exists in the latter).