We have an intermittent error from several of our web applications all saying the same thing:
System.Data.SqlClient.SqlException: 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) ---> System.ComponentModel.Win32Exception: The network path was not found
We're unable to reproduce the issue on command; everything works 99% of the time. We see these errors between 2 to 3 times a day. The time that it occurs is not consistent. We have two separate servers running in AWS: an SQL Server Standard 2016 server, and a separate server running our .NET Web Applications. The web applications connect via ADO.NET.
How do we begin to diagnose these errors?
Are there logs we can turn on? What should we rule out first?