Error while Adding Domain

Error while Adding Domain

Hello,


1. I already have an website in another website, Now to create Business mail, I need add Domain in control panel ?

2. I tried to add Domain , But it showing error ( This Operation has been restricted. Please contact support-as@zohocorp.com for further details )

3. After Adding my Domain, Will Zoho Maill will get Full access, If anyone Subscribed in my website, will I get Mail or Notifications to Zoho mail ?

Hope You will Respond Soon. 
Please Provide Information pointwise.
Thanks