Hi everyone.

After OST suddenly stopped fetching emails from MS Office we upgraded our setup to the latest build osTicket v1.18. As the problem persisted we removed the email-accounts we had set up as well as the oauth plugin and started from scratch following the OST guide: The setup works fine and emails are being fetched during the account creation when we save the settings.

However automated and semi-automated fetching fails, while clicking to save the email account settings correctly fetches all mails without issue.

The cron job returns the following error message:
PHP Fatal error: Uncaught Error: Call to a member function setConfigClass() on null in phar:///var/osticket/include/plugins/auth-oauth2.phar/oauth2.php:640 Stack trace: #0 phar:///var/osticket/include/plugins/auth-oauth2.phar/oauth2.php(467): GenericEmailOauth2Provider->getPluginInstance() #1 phar:///var/osticket/include/plugins/auth-oauth2.phar/oauth2.php(480): OAuth2ProviderBackend->getEmailAuthBackend() #2 /var/osticket/include/class.email.php(902): OAuth2ProviderBackend->refreshAccessToken() #3 /var/osticket/include/class.email.php(784): EmailAccount->getOAuth2AuthCredentials() #4 /var/osticket/include/class.email.php(756): EmailAccount->getCredentials() #5 /var/osticket/include/class.email.php(744): EmailAccount->getFreshCredentials() #6 /var/osticket/include/class.email.php(474): EmailAccount->hasCredentials() #7 /var/osticket/include/class.mailfetch.php(245): EmailAccount->isActive() #8 /var/osticket/include/class.cron.php(25): osTicket\Mail\Fetcher::run() #9 /var/osticket/include/class.cron.php(110): Cron::MailFetcher() #10 /var/osticket/include/api.cron.php(15): Cron::run() #11 /var/osticket/include/api.cron.php(45): CronApiController->run() #12 /var/osticket/api/cron.php(23): LocalCronApiController::call() #13 {main} thrown in phar:///var/osticket/include/plugins/auth-oauth2.phar/oauth2.php on line 640

Our setup:

osTicket Version: v1.18 (724de45)
Web Server Software: Apache/2.4.54 (Ubuntu)
MySQL Version: 10.6.12
PHP Version: 8.1.21
PHP CLI Version: 8.2.8 (cli)

We have scoured the forum and www for a solution and tried everything we could find to no avail.
Any suggestion on how to solve this welcome.

P.S.: Since I'm here - You guys are doing and absolutely smashing job and OST is absolutely epic! Thank you for all your blood, sweat & tears keeping this going! :