I wanted to go on a server and it said java.lang.NullPointerException:group.Also that there was noconnection any server that I had

I went to play a hunger games server as usual and I clicked on it and it said java.lang.NullPointerException:group.Also it said that there was no connection even though that I go on the internet .After that I said to myself that's weird so went to singular player mode and tried to go on a world and it crashed