Translation:I am in the same hotel.
At the hotel is fine in US english
I think there must be some difference between US English and English English here. In English English " I am at the same hotel" is perfectly acceptable, but not to Duolingo.
Or maybe they have forgotten to add it to the database.
"I am at the same hotel" accepted 7/27/18.
I'd imagine you would say this to someone on the phone who you can't see but is in the same (insert place) as you. May somebody please add to my post? ¡muchísimas gracias!