I purchased a secondhand UR824 and it either hadn’t been registered before or it had been de-registerd by the previous owner. I registered it in MySteinberg under my own account succesfully. I didn’t have a license for the Basic FX suite so I contacted support and they provided me with a new license for this. I think the registration of the hardware is the key to it. Have you tried doing this in MySteinberg? If not are you able to contact the previous owner? It might be they could de-register the hardware which would allow you to register and then get the FX license. There is an option to delete registration in the Hardware tab of the MySteinberg account.