This doesn't sound like a Messenger Plus! problem, but more like a problem with that particular account.
Nope, you don't need to set your router to anything to allow multiple MSN Messengers to run. They all use the same connection anyways.
But do note that patching Messenger can cause unwanting side-effects. Although, if you just patched it with MessPatch to allow for polygamy (multi-msn), it shouldn't affect anything.
Try to sign in with that other account without using a secondary Messenger. Does it work then?
You may also try
these instructions to try and fix that secondary account (your girlfriend's account?).
Iether way, I doubt this has anything todo with Messenger Plus! or MessPatch. However, you can test this out by using only one of the two and by using neither:
- To use only Messenger Plus!'s polygamy: reinstall or repear Messenger
- To use only MessPatch's polygamy: uninstall Messenger Plus!Live
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