Help I cannot connect to my steam friend's game

I cannot connect to my friend's game in starbound without making a new character but I have to make a new character every time I want to join. I went into the files of the game and I can delete 3 of the player files to connect 2 more times but then nothing loads in the world and my friends say that they start to get a lot of server lag. I am on a 2011 macbook pro on macOS High Sierra version 10.13 and using an iphone hotspot and I have AT&T. None of my friends are having this issue at all and they can connect to each other. They cannot connect to my game though. The message I get is "Join Failed! No server response received"