1. I loged in to zoho with telephone number: 0909691884 succesfully (its email: pharmasys.vn@gmail.com) 

2. I clicked on Enalble email hosting - screenshot attached

3. Then I add a domain pharmasys.vn to the email hosting however zoho' system issue an error:  This domain is already associated with this account "*****84  (screenshot enlosed). And that problem encounter me to do any more action 

Please help us to solver the problem or guide us on how to overcome this

Thank you very much