I have an application that has been running for years. Starting in early January, I've started seeing connection errors when simple queries run against the database. This only happens to maybe one query every couple of hours, but this never happened at all for years. I say that after reviewing the application's log files; it isn't just a case of not having noticed until now.
The application and database server are on the same system, so I'm not sure what to look into with regards to what can cause such an error. The default solution I would try would be to reinstall the instance and hope for the best, but I'm hoping for a more targeted solution.
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.)
The SQL Server instance is configured to allow unlimited connections.