friends can't join my server

well, as the title says, no one can join my server;;

i changed my wifi (net to vivo, i like in brazil!) yesterday and this issue started. my friends can join other people's servers, but not mine and i can join my friend's servers and random people's servers, so i have no idea on what to do? i don't know what it might be causing the problem. i tried to make a new server without mods, but it still has the same issue. when my friends are trying to connect to my server, they doesn't apper in that one spot where they should apper when someone is logging in a server. i'm starting to freak out cuz dst is my favorite game, and i love to play with my friends;;