marcrobinson, you can add this key to your DC's as a workaround without removing the update. Unfortunately once a fix is released im not sure if you'll need to clean this key out. This was provided by Microsoft Support

reg add HKLM\System\currentcontrolset\services\kdc /t REG_DWORD /v ApplyDefaultDomainPolicy /d 0 /f

ApplyDefaultDomainPolicy

REG_DWORD

Value: 0

Thank you for the information - and I will pass it along to my teammates. We did the audit reg key (kb5020805) to collect more information and permit authentication, but it still did not help. FYI - this patch can cause SolarWinds services to fail. I suspect many of the back-end API calls. Similar to what I noticed with Atlas and SWQL Studio. We are still evaluating - and considering whether this patch is worth it. In other words - waiting for the "fixed" patch. 

EDIT: I just looked at several KB articles related to this patch. First reaction 'Ewwww.'  I see the trend coming, and hope its something that does not cause more grief. KB5020805, KB5021130, KB5021131 all show methods to handle the change and give us the roadmap. 

marcrobinson, i know exactly how you feel, i think in our environment we are waiting for the fix to come out instead of deploying this registry key. When we were trying to figure out what was going on, we saw no entries of the advertised event ID's, so that was less than helpful. At least Microsoft has acknowledged that it is a bug and the patch is not behaving as intended. 

marcrobinson, i know exactly how you feel, i think in our environment we are waiting for the fix to come out instead of deploying this registry key. When we were trying to figure out what was going on, we saw no entries of the advertised event ID's, so that was less than helpful. At least Microsoft has acknowledged that it is a bug and the patch is not behaving as intended. 

I want to close this loop. Microsoft released some Hotfixes to address this issue. See this article from bitdefender.

Microsoft Releases Emergency Updates to Patch Kerberos Authentication Issues (bitdefender.com)