BizTalk Error code: 0xC0002A21, An error occurred while attempting to access the SSO database

I have a BizTalk 2013r2 Standard Edition application server with a dedicated (Separate Sql Server) hosting the BizTalk databases.

Just lately, I've started to see a pair of errors in the event log. Typically these are raised about every couple of hour but there's no clear pattern - sometimes they can be as close a 15 minutes between two pairs.

The Error reads:

An error occurred while attempting to access the SSO database.


Function: LookupXp
 File: lookupserver.cpp:296
 Timeout expired.  The timeout period elapsed prior to completion of the operation or the server is not responding..
 SQL Error code: 0xFFFFFFFE
 Error code: 0xC0002A21, An error occurred while attempting to access the SSO database.

This is follows by a similar warning:

SSO AUDIT


Function: GetConfigInfo ({9AB60D40-9719-453D-89BD-3DAF212A7C17})
 Tracking ID: 2ad795a0-4d62-4545-a823-fd0ea492a833
 Client Computer: kochanski.xxx.local (BTSNTSvc64.exe:3152)
 Client User: xxx\biztalkhost
 Application Name: {DC9847A1-4D85-4C8A-B9D3-A58AFE352649}
 Error Code: 0xC0002A21, An error occurred while attempting to access the SSO database.

This is now a serious problem because on at least one occasion, this has prevented BizTalk from firing against the scheduled task adapter.

Anyone come across this error before?

Has anything changed on a network level which might have caused a network glitch between your BizTalk server & your SQL server?

I've seen the same issue in the past after a SQL failover and restarting the WMI on the BizTalk-nodes solved it back then.