How many times have I seen this message on a blank page when starting browsing Sharepoint 2010 or the Central Administration ?
Well, a lot of times, believe me, but yesterday was a new one !
A friend called in despair saying that their Sharepoint installation (intranet, 1 Front end webserver and one shared SQL Server with a Sharepoint instance for isolation) had stopped working and that the only message in the browser was : “Cannot connect to the configuration database”.
Ususally it has something to do with the database being irresponsive. After a quick connection check to the instance running Sharepoint databases, this wasn’t the problem.
I could access the databases with SSMS and I could even create an ODBC connection from the Sharepoint Front End server to the database instance.
My friend told me – after a few minutes of thinking about possible causes – that they had just changed the Primary domain controller and the DNS address had changed from 10.x.x.13 to 10.x.x.20.
Bingo that was it ! I remembered reading some times ago a post stating that whenever there was a change of IP address for the DC a Host (A) Name record should be provided in the DNS to ensure continued connectivity between Sharepoint and the SQL Server databases.
So remember to check those Host Name records whenever you see “Cannot connect to configuration database” and there have been some changes in your network configuration.