Kerberos Issue - Anonymous Login
Could be this.  Part of Security Patch that came out in Nov. &amp; was updated in Dec.
This explains the problem:
https://support.microsoft.com/en-us/topic/managing-deployment-of-kerberos-s4u-changes-for-cve-2020-17049-569d60b7-3267-e2b0-7d9b-e46d770332ab
This contains the patch under Security Updates header:
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2020-17049 (first 1 is for 2016 &amp; up)
First, make sure all AD Servers are on the same patch.
Create &quot;enforce modes&quot; create reg key if not there. Set to 1.  Let sit 7 days to reset.
Change to reg key to 2. Restart Service or wait another 7 days.