I am on Android trying to get into a server while using mobile data. When I try to join, it says "you cannot play with your friends without being on WiFi." And I think that is odd because I know for certain none of my friends are on the server I am trying to log onto. There also was a button I pressed called "use cellular data" that I thought would help, bit it didn't. Instead, it made the server list disappear, so I turned it back off again. I also recently imported a custom skin I made, in case that helps.