shame on you to call a person stupid just for misunderstanding your question you already didnt say if you bought monthly key or just trail .. anyway for your problem I had the same and turns on they were 2 devices using the same key and it was mistake from the seller .. and to solve it there is view ways 1- you need to talk to the seller you thay you bought the key from and ask for another key with screenshot of your key with the problem and make sure not using by another person
2- open ticket from support here in the website to see if the key is expire, unvaild, or used by 2 devices they are very auick to reply and very helpful.
3- copy and paste the key .. clear the last character and type it again ( if you still have the same problem dont try again because this will ban you for few hours) try again later after 2 hours .

dont buy cheap key beacuse they mostly are just cheaters and sell the key for two players.