Regular disconnects: WOW51900319

For the last few days I have been getting regularly disconnected with the error WOW51900319. Normally I can reconnect straightaway.

Sometimes I get it very regularly - like every 30-60 seconds for five minutes. Other times I can play for 45-60 minutes without issue.

I have tried: turning off addons, uninstalling addon loader, removing cache/wtf folders, scan+repair via bnet launcher, reinstalling game, checking all drivers are up to date, basically everything I can think of.

I have not put a ticket in yet because in my experiences responses are normally not helpful and will be “check the forums” or in this case likely “check w/ your ISP”. But I played for years without issue until this last week.

I just wondered if anyone else had any suggestions before I give up entirely? TIA!

EDIT: For anyone that finds this in the future. A few days after my post, when I logged in to play, there was a game update and that seemed to initially fixed the issue. I was able to play for a few days without any disconnects. BUT after the weekly maintenance today, the game now lags so much its basically unplayable (although it doesnt disconnect at least)

I started getting dcs early Jan, fixed it by capping my frames but now some mobs/npcs and occasional players I run into have a weird thing where they like glitch a foot ahead, urs similar or a different kind of lag?