To expand on my last piece:
After the latest update the server list is completely empty, and I can't connect by IP. Nothing has changed network wise.
I'm running 2.5.6.49314 and did a complete reinstall overnight with no effect.
I tried connecting through a vpn, no effect.
All other games and connections work fine, and single-player works great, the best performance in a while.
I have now ran another repair, and tried having windows defender full off, still nothing.
Any ideas of what could cause this or things I could try?