Issue 1: Login failure

Severity: 14, State: 11. is what it shows in the logs.

In ring buffers below are the error codes.

[highlight=#ffff11]ErrorCode: 0×534

CallingAPIName: LookupAccountSidInternal

APIName: LookupAccountSid[/highlight]

Which indicates that SQL Cant resolve the name against AD.

But one of my another SQL instance is also hosted on the same node of the cluster where in the user is having no issues connection.

I ran the below thing which was intresting to see on 2 different SQL instances that are hosted on the same cluster and same node.

EXEC xp_logininfo 'Redmond\UserAlias','all'

On Problematic instance: It did not give me results.

On other sql instance: It gave me list of all the Security groups the user is part of.

Oh i should mention this. UAC is enabled on this node.

can you suggest further?

Issue 2: CMD execution failure with access denied error.

we can take this up once Issue 1 is resolved.