Brand can not be registered with provided address since duplicate threshold limit has been reached for it.
Reusing addresses for Sole Proprietor Brands is not allowed. Each Sole Proprietor Brand should have a unique address linked to it. It is possible that the Starter customer profile bundle associated with the brand you tried to register has a duplicate address linked to it.
Please edit the connected starter customer profile and link a different (unique) address to it. Once updated and submitted for review, please resubmit the Sole Proprietor Brand registration request.
Additional help resources