We're hosting a site on cf 9 server.
Sometimes the users get an error:
The server encountered an internal error and was unable to complete your request.
JRun closed connection.
It's not all the time though, there doesn't seem to be a pattern as to when someone gets that error. The default page itself isn't doing anything, it's a login form that waits for input.
I allowed all IPs, I think, I have this: