Unable to place relics on the altar.

I am unable to place the relics onto the altar even after doing the quest in act 2.

I orignially didn't go to the fellshrine ruins, and have been playing a bit in the sanctum. I did manage to kill the first floor boss as well as one of the minibosses that seemed to unlock something for the sanctum prior to starting the act 2 questline.

After doing the quest I recieved a relic, but i'm unable to place it onto the altar at all.

My achievements say that I have unlocked the altar, but I don't seem to be able to interact with it at all.