I had a similar issue a while back now. There was a second AD domain behind a firewall that Unity did not need (nor was it allowed) access to. However, occasionally during an import of user accounts there would be a reference to this domain in some fashion on a user object. I would then get the same errors you see now. I opened a TAC case and was provided some steps to modify the DC/GC Reconnect settings; however, it did not resolve the issue so I inquired about deleting the AD Domain directly within SQL. I was told this was perfectly viable and would stop Unity from searching for the unwanted domain. So here's what you do:
Open SQL Server Enterprise Manager > Expand Microsoft SQL Servers > Expand SQL Server Group > Expand Local
Expand Databases > Expand UnityDb > Select Tables
Highlight the ADDomain table, right click and select Open Table > Return All Rows
Select the entry for the AD Domain that Unity is not associated to and select Delete
Hailey
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