So, I'm not sure if it's just his end, but when I start a netplay room with a friend he can't seem to get the start button to work for him to join. He goes into single player and it works just fine. I haven't been able to test if it's just him or not as I can't join one of his games cause I keep getting disconnected. He's reset the controls multiple times and the only buttons that work are the directional (as far as we know)

Edit: Scratch that, apparently it's all games from the specific emulator. The rest of the buttons work we found out, except the start button. So this might need to be moved the appropriate section.

Edit 2: So it's only specific versions of the MAMEhub that are causing the problem. On Metal Slug - Super Vehicle-001 everything works fine, but on Zombies Ate my Neighbors and Super Double Dragons it refuses to work the same. I have found a work around for this though. If the person who set up the room (1st player) sets an extra button for the 2nd player start button, then they can push the start button for the 2nd player. 

What if you use Mednafen?
Do you have the same problems?

Have you also tried to reconfigure the controls after joining?

We were having lag issues with mednafen in the beginning but it started working fine a couple days later so we started using that.

Out of curiosity, when did you first try Mednafen for netplay?
I know pre 2.30 we had desync issues, so I am just wondering if it started working better after the update.

I don't remember the exact date, but it was 1 or 2 months ago. Our first attempt was trying to play the Super Mario 64 Multiplayer hack, and the desync on it was so bad. We  later tried Mario Party 3, and it was still really bad. So we just jotted it down as N64 games not working too well for netplay and/or because of the distance between us since we live in different states. so we stuck to Pre N64 games. It might have been because of that I kind of wrote Mednafen off as broken and kept using MAMEhub.

strife98 : I don't think n64 uses mednafen.
It uses either 1964 or mupen64plus.
Mupen typically works better for netplay but doesn't have the ability to change controls without manually changing the configuration files.