@kautuk_sahni no, none of the suggestions so far have addressed the issue.

Yes, we have raised numerous tickets for this issue, but Adobe has not been able to provide a solution so far.Yes, restoring from backup (obviously) works, but is not a viable long term solution.

There is no heap error before this error. We use 4GB max heap, 4 cores.

We can track our changes and we did not make any unusual changes before it happened. Just normal content changes. This is our stage environment (out of dev --> stage -> prod). 

AEM 6.5 SP194GB max heap, 4 cores We have the very common "AuthenticationSupport service missing. Cannot authenticate request." error.There are no errors in the logs prior to this one (we created a custom logger for Info and org.apache + com.day.cq). This is our stage environment (out of dev --> sta...