Initial sync imploded after *2 days*


I plugged my node in and it has been synchronizing over the weekend, it has been at least 48 hrs.
Today it got to 90% then suddenly when I refreshed it, it came up with the following:

502 Bad Gateway


I can’t refresh, I cant sync, I can’t login… what would this be?

I am not coder but can try and figure it out but would love tips on where to look.