An unhandled exception occurred while processing the request. Win32Exception: An existing connection was forcibly closed by the remote host

Azure .NET web apps connecting to an AWS SQL database kept throwing up this error sporadically, seemingly without any pattern. The full message was this: An unhandled exception occurred while processing the request. Win32Exception: An existing connection was forcibly closed by the remote host. Unknown location.SqlException: A connection was successfully established with the server, but... » read more