ArcGIS Server 11.5 Upgrade Requires Domain when Logging In

[MRantala]

We recently upgraded a stand-alone ArcGIS Server (from 11.3 to 11.5) that uses our Active Directory (Windows Domain) as User Store. Since making the switch, we now have to prefix our user name with our Active Directory domain (e.g. domain\username). Previously, we just used our username.

That is fine for logging into ArcGIS Server Manager but it is a problem for our items in ArcGIS Online that use stored credential and in our proxy configurations (used for our remaining Web AppBuilder applications). If we change them, they seem to work but the problem is proactively finding all cases.

I do not see anything in the documentation saying this was a designed change in the way that ArcGIS Server or if there's a configuration option so we don't have to specify the domain.

Wondering if anyone else has seen this when upgrading to 11.4 or 11.5? or has any suggestions.

Thanks

[MRantala]

One other piece of information, when checking how the Windows Domain was configured, I see that it was configured using domain\username . I tested and just using username passed the "Test Connection" test. I wonder if I went through the entire configuration process, it would resolve the issue. 

[valenj88]

See my thread here: 11.5 Authentication Issues: IWA alongside Anonymou... - Esri Community

I'm about to meet with an ESRI tech to walk them through this issue.  I'm guessing it's a bug though.  It's causing portal login issues in Pro as well.

[MRantala]

Thank you, we also have a ticket open to see what Tech Support can tell us. Seems likely that we have a common root cause for behavior change. 

Addendum: Esri has recreated this issue and it may be logged as a defect.