Joining Servers Is Not Working!

I have been having this problem for a long time now... When I join the server on this account (racer123678) and try to join a game the normal thing happens where the item selector pops up and asks me to pick a class. So when I try and go pick the class nothing happens it just closes the item box and I stand in the box the you spawn in. I have no idea what to do. Please get back to me as soon as you can Thank you! (Also it works on the other account ToxicPandaGaming) I also have access to zero commands so typing /kill or anything else doesn't work. Yes I using the resource pack. I have tried everything please help! The picture have with this is what I am experiencing.