SQL Error - has more columns than were specified in the column list

I'm trying to retrieve results from the below query but keep getting this error message: Msg 8158, Level 16, State 1, Line 1 'a' has more columns than were specified in the column list. My query: select * from (select customer_key as customer_id, updated_by as [Help Desk] from permission) a (nolock) where [Help Desk] is not null