Can find other players with internet box but can't with internet phone sharing

[Esanqueris]

Hello there !
After a lot of try to connect with a friend, we found out what the problem is, but we can't resolve it.

We finally found online players but only one of us could because if we are on the same internet connection, the last one to connect just crash.

So i tried to connect with my phone's internet (with a classic internet share) and then ... doesn't work anymore, i can connect but it never find anyone.

I already looked for answers and found nothing (so i'm sorry if this topic already exists, but i really didn't find).

If someone can help me, that would be great !