The domain which you have entered belongs to a different deployment/region

The domain which you have entered belongs to a different deployment/region

I tried to register a new domain for Zoho Mail for a client but it failed to complete the registration and the domain now appears to be linked to my personal Zoho account although doesn't show in the Control Panel for me to be able to deregister.

I realise I need to register using my client's phone number now, but its not letting me do so. It just comes up with the message:

"The domain which you have entered belongs to a different deployment/region"

Can you plese disassociate the domain bettorfootball.co.uk from my account so I can help him get set up?

(I've tried emailing support but am going around in circles)

Thank you.