Northrend quests glitched

My friend Maximiliss and I (Nathansdad) have been trying to quest in Northrend on Icecrown, but none of the quest objectives get completed when we do them. For example, we kill a mob for a quest and it doesn't give us any progress. For the quest Blighted Last Rites, we tried to test the thing it wanted us to on the prisoner and he just disappeared without giving us the objective. This has only really been happening for us today, is anyone else experiencing this? All the quests we've tried from Howling Fjord, Grizzly Hills, and Dragonblight.

Thanks

Okay, we got in a dungeon and afterwards everything was fixed, so maybe our instance was glitched? I have no idea, we had tried restarting our games and everything and nothing worked. Does anyone know what caused it? Thanks

maybe you guys converted your party into Raid Group? in that case you can not complete common quest