So I am thinking that if you both are having the issue there is a good chance its a Windows update issue thats killing RSLinx
This has happen to me several times
So....something for thought. In the ML1400 channel configuration, you can disable incoming Ethernet/IP connections. Could this be the case?
You can just check that in channel configurations without being online. See Red... This is a ML1400...
That is, if you have a copy of the program.