I tried to register on the COAP 2018 site this morning.I do have a valid score card of this year's gate.But it's giving me error saying "invalid registration number".I tried all combinations of the registration number(since it was instructed to enter the registration number without paper code).but despite all attempts it's still showing that same error.Can anyone else confirm if they are getting a similar error,or if there is any mistake on my part.