Hi, Jeff
I never said that Mobilink showed code '-10001' in the log. There was no code, only the message 'Protocol error'
The mobilink client machine had a user profile, which alternated it's internet options for some obscure reason. Some of the time it went through firewalled proxy and on other times it went directly to the server. So, part of the time he could reach the server and part of the time he could not.
When it went out through the proxy, I tried to simply open the relay server URL in the browser and got a FW error. So, basically, the mobilink client should have returned 'NOT FOUND' or something like that.