It may simply be the amount of people online right now fluff. Or it could even be a bug. I would just give it time. But you could try changing your rendering system or resetting your internet to see if that helps.
Sometimes that could be the reason.
Depending on the amount of people + plus how strong your internet is & even the amount of 'objects' in a map can make anyone crash in a map before stepping in.
I had that issue happen to me a lot whenever I went to bonfire before the update.
Hopefully you'll be able to get on once there isn't many people ^^