Thought it was a SQL problem as the following errors show up periodically in the SQL logs but these existed far before I noticed this SMC connectivity issue so not sure.
Date 12/29/2014 6:19:02 AM
Log SQL Server (Current - 12/29/2014 6:19:00 AM)
Source Logon
Message
Error: 18456, Severity: 14, State: 11.
Date 12/29/2014 6:19:02 AM
Log SQL Server (Current - 12/29/2014 6:19:00 AM)
Source Logon
Message
Login failed for user 'DOMAIN\SERVER$'. Reason: Token-based server access validation failed with an infrastructure error. Check for previous errors. [CLIENT: xxx.xx.xx.x]