"We were unable to authenticate your login. Usually this means that a newer client patch is now available or the username or password you provided are incorrect.....etc etc etc"
But, here's the thing.
a) client was fully patched, but it still uses the AOS loading screen despite the fact that it came from a ML setup.
c) the client isn't being picked up on the server
EDIT:
I changed login.cfg to login.scp (and then to login.mul) and I've tried using the IP I get at whatismyip.com and the one that the server says it's listening to and when I put in my password, the client crashes.
