This user is not allowed to add in Zoho. Please contact support-as@zohocorp.com for further details

This user is not allowed to add in Zoho. Please contact support-as@zohocorp.com for further details

Hello,
We're getting  This user is not allowed to add in Zoho. Please contact support-as@zohocorp.com for further details error while trying to add any new user to our domain email. The email is @ overstruct.com

Please reply. Thanks.