Over the past two days, many rooms have been 'crashing'. (https://i.imgur.com/LLl26xl.png)
I can't determine from my end what the cause is, but from what I've observed, it seems to be someone using an exploit to crash the rooms.
It appears to be something that targets the room's API - or the format data is stored in the backend - as trying to access json.php?fast=1 will redirect back to the broken room page.