[SOLVED] Upgrade from 14.10 to 15.0 broke issue notifications

Upgraded gitlab-ce from 14.10 to 15.0 on Ubuntu 18.04.6 LTS. Afterwards issue notifications stopped being sent on both new issues and issues that had previously been sending notifications. SMTP is not broken though because testing smtp does work:

Notify.test_email('destination_email@address.com', 'Message Subject', 'Message Body').deliver_now

Using that in gitlab-rails sends emails without any problems.

Not sure where to look for errors in the gitlab logs.

gitlab-ctl reconfigure and reboot fixed it. All the emails from the last two days just got sent all at once.

I spoke too soon. A reconfigure and reboot fixed one of my gitlab instances but not the other.

I still need help please.