Whilst I appreciate that the bug may be recent, using this forum to discuss it is not welcome. The Recent Game Updates forum is for players to discuss content released intentionally in the past two weeks. As your thread is better suited to this forum, it has relocated here.
I echo the advice offered above and suggest that you submit a
Bug Report
, so that the QA team can track down the issue to fix it.
A 502 Bad Gateway Error means that the web server you've connected to is acting as a proxy for relaying information from another server, but it has gotten a bad response from that other server. It's called a 502 error because that's the HTTP status code that the webserver uses to describe that kind of error.
Jagex/JMods might be working on it in order to get everything updated/upgraded.