What version of WinMx are you using now, and what patch do you have?
Bad news is:
There is a known bug with 3.53 that causes disconnections with room lists and incomplete lists for secondary users.
Good news is:
There is a patch that was made that can fix this, just need to make sure of what patch you use to connect now since FrontCode caches are no longer in use so that we dont mess up your main connections.