Because PTS is technically not in the EU, it's in the US they've just copied the EU server over this week. So you're playing on NA technically speaking and that's the server that gets attention, the actual EU server can scr*w itself for all ZOS cares.
Yesterday on 7/27/20 there were login issues affecting the PC/Mac EU megaservers. These issues are now resolved. For this reason we are closing the discussion.