CA works fine, "Cannot connect to the configuration database" for a site collection?

Hello,

I'm moving all the DBs of a Sharepoint 2010 farm from a SQL2008 server to a SQL2012 server. I created a cliconfg.exe TCP/IP redirect that works fine for the CA site and two of three site collections. One of the sites gives me the "Cannot connect to the configuration database" error.

I checked the old SQL server and new and the WSS_Content_Site3 db is on both, mdf files are the same size. I tried detatching/reattaching the db in question but nothing changed.

Any recommendations on what to check? Would there be anything in the 14/Logs?

Thanks,

Scott