I am running MS-SQL Server on Windows Server 2012. From time to time I get this Exception:

Server Exception : System.Data.SqlClient.SqlException (0x80131904): Connection Timeout Expired. The timeout period elapsed during the post-login phase. The connection could have timed out while waiting for server to complete the login process and respond; Or it could have timed out while attempting to create multiple active connections. The duration spent while attempting to connect to this server was - [Pre-Login] initialization=6; handshake=9410; [Login] initialization=0; authentication=1; [Post-Login] complete=5627; ---> System.ComponentModel.Win32Exception (0x80004005): The wait operation timed out at

When it happens I get hundreds of them in a few minutes and after a while it recovers. I couldn't find anything useful on the web. I would appreciate any help.


  • Is there a multi-subnet availability group involved? If so, the AG could be failing over and it takes a while for the record in DNS to get updated... – Ben Thul Dec 20 '13 at 23:41
  • Thanks @BenThul . there isn't any multi-subnet availability group involved. it is an IIS server approaching an SQL server on the same instance. no IP's involved. It that what you mean? – Orr Dec 21 '13 at 17:56
  • 1
    Well... nuts. I guess I would monitor CPU on the machine and see if spikes correlate to the times when you get these connection timeouts. – Ben Thul Dec 23 '13 at 3:45
  • I've started had this a couple of times on servers with both IIS and SQL server. The most recent time was on a different machine. This post stackoverflow.com/questions/1421978/… suggests memory use and swapping - in case that helps? My problem appears to be compounded by an Umbraco sute then taking 100% of the CPU forever :( – Ian Grainger Jun 1 '15 at 9:14

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