Ice Barrows Dungeon

I got the key from the Fate of the Fallen Quest and got a key, but when i gave it to the collector, i wasn't able to go inside and it immediately reset for some reason. Is this a glitch, did I have to do something else, and how do I get another one?

 

It was probably a bug, after giving the key to the key collector, you should've been able to go in, but if it took your key and didn't let you in, you can buy the key on the market or kill the Ice Barrows Key Guardian, which can be found around the Frozen Lake near Nesaak and the Ice Barrows dungeon. He can also be found on Llevigar Plains but that is quite the trip. Also, he doesn't have a set spawn point where he will always spawn, so if you want to find this mob, you just kind of have to run around until you see it.