[Khoros Community] Mail notification delivery issues

We are still working to address the root cause of the issue, but the following things have been clarified:
1. Emails are working, but they are delayed for any Gmail addresses.
2. The delays are limited only to customers using a custom DKIM setup; customers using our standard Sendgrid solution are not affected.
Affected customers may request switching to our standard Sendgrid solution as a workaround.

We have identified a widespread issue affecting email notification delivery across multiple customer communities. Users are not receiving expected email notifications from our platform, though in-app notifications continue to function normally.

The root cause has been identified and we are working to re-establish the normal flow.