EA-Valgard
UPDATE: I've tried some things over these last few days. I've also started school so that's why I'm responding late. Sorry about that...
So I can still play as long as I use Quickmatch and or History, but the server browser on Battlelog on my PC, My iPad, my Phone or in-game won't show any servers.
Normally I play on a wireless connection, but I used a wired connection to start. No luck with re-starting Xbox or router.
My router had those ports forwarded by default, but to give it a good shot I un-forwarded them, restarted the router, forwarded them and restarted again. Still no results.
I changed to static I.P. and afterwards I restarted both my router and my Xbox. No results.
I can't read the troubleshooting steps you linked as they are in Dutch or German...
Now I can still play, but I can't find my favorite servers or servers friends are playing on. Kinda annoying seeing as I can't see which servers have a good connection, and I can't sort out hardcore from normal, ranked, etc.