Problem with adding new user with own domain

Problem with adding new user with own domain

Hi,

I just join ZOHO and paid the license : Standard 10 GB Edition

I tried to add some user using my own domain, which I also applied fro ZOHO. But the system always gave me the following feedback :

Max user license limit reached. Please purchase/ugrade license to add more user(s) with mailboxes.
Please someone help me how to fix it or did I made anything wrong with this?

Thanks