FortiAP FAP-221E (used) already registred?

Hi guys,

a friend of me is creating a new (small) office. In the old rooms he found an old (used) FortinetAP221E.

He tried to use it but he said "on adding it to FortiNet" it says "already registrered to another company".

How can we solve that issue or where is that shown? I tried to register on FortiNet Asset Management now by adding the serial number, but it says "Invalid input data".

Maybe someone has a hint for us?

Thanks.

Andy