Hello.
I found some unidentified items in the Den of Evil.
I’ve picked up an unidentified Hand Axe and I’ve tried to identify it using a book and also tried using the scroll itself.
I also have a dagger i found that I cannot identify. Same thing.
Update: about 5 minutes later, my dagger just randomly identified itself while i was looking at items with charsi. My hand axe is still unidentified.
This is a bug 
I’m also having this issue. I am able to identify items found elsewhere in act 1, but not items found in the den of evil.
Try closing the game… It will delete all your characters.
Was getting the same thing. I had to shift click the item, then retry identifying it. Seemed to work. Bug isn’t related to just den of evil drops, at least for me.
I had the same issue and now believe it is related to the servers being overloaded and unable to process the data.