I cannot think of anything to help you, if the vanilla game multiplayer works fine and EF doesn't, other than trying to make a clean install. If you claim that the vanilla game cannot login into relic online after you installed EF, that's not our fault. Eastern Front doesn't modify any vanilla files so that issue might be caused by something different.
Also, remember the only CoH game that connects to relic online is the new steam version. If you try the other versions with EF you won't play it correctly (and those aren't 2.700 either).