I have a large, self written module.  All the data is in a separate database, secondary to the main DNN one.

One component is a scheduled task, there are other standard display/edit module components.  All share the secondary database, all use the same connection string, picked up from the web config.  The online portion of the site is working perfectely. 

Yesterday I discovered that the scheduled task has been failing since the early hours of September 27.  My last code signoff was Sep10, so the code ran happily for 17 days.  The failure is "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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)"

The site is hosted at PowerDNN.  The connectionstring uses SQL Server authentication.  The SQL Server (for both the DNN database and the secondary) is on the same machine as the Site.

I'm out of ideas.  I feel that it has to be a change in the environment that stops the code from reaching the SQL Server.  I cannot imagine what it might be that allows the online pages to connect, but fails when the scheduled task connects.

If anyone has any idea what this might be, or can suggest any checks I can ask PowerDNN support to try.  I'm *very* interested.

Thanks for reading so far.