Continous refreshing don't work on me.
exactly this, when this happens don't refresh again, seems like if you refresh faster the error 502 will remain, so just w8 some minutes and try again, you will see how the forum works again.
it happened to me few times and thats the only way i know that works, also if im not wrong i remember that theymos already reply the same about it, but cant find the thread now