Friends cant connect to netplay

[Brendong]

I got an issue with dolphin net-play on version 4.0-6048 for Melee. One of my friends can join just fine although some of my other friends try to join, they get the error message "a net-play window is already open" and it kicks them out of the game. As the host i can see their name pop up in the netplay lobby although their ping is usually around 30000000 until they get kicked. I also cannot connect to their games either. Our net-play worked on version 4.0-652 of dolphin but not on the new versions. Anyone know what the issue could be here?

We made sure all graphics and configuration settings were the same.
All firewalls turned off.
EDIT: Were using the traversal server method

[NKF98]

Does your netplay still work on the 4.0-652? Do you have memory cards disabled? Are you all using the same version?

[Brendong]

(04-28-2015, 01:31 PM)NKF98 Wrote: Does your netplay still work on the 4.0-652? Do you have memory cards disabled? Are you all using the same version?

Yes to all of that. 4.0-652 still works fine but traversal server on the new version will not. Mem cards are all disabled and were all on the same version of dolphin. We also tried version 4.0-6033 and that didn't work either. Any help would be appreciated