Can't Join Servers, My Server Doesn't Show Up

[Fwizy]

Last night and every other day before today, I could host a server and my friends could join and ride with me. I woke up this morning and tried to play with them again, and my server doesn't come up on the list nor am I able to join anyone. The only message it gives me in the box that comes up when I try and join someone is "??". Anyone know what could be causing this issue? I haven't changed anything in my files nor have my friends.