We might get below error when we open sqlserver errorlog in SSMS or using xp_readerrorlog or sp_readerrorlog

{

Msg 22004, Level 16, State 1, Line 0

Failed to open loopback connection. Please see event log for more information.

Msg 22004, Level 16, State 1, Line 0

error log location not found

}

1. If you get this error in Clustered instance of SQL Server then disable “shared memory protocol” in client configuration.

2. Check if you have wrong alias created and fix them.

3. UAC can also cause this (You might see following message in sqlserver errorlog “Reason: Token-based server access validation failed with an infrastructure error. Check for previous errors”).when you run SSMS run it in elevated mode (right click SSMS–>Run as administrator).

4. OOM condition in sqlsever can also cause this error

5. Executing xp_readerrorlog from DAC connection can also cause this error.