Group Creation Failed

Hello,

I have followed the instructions from this page:
https://www.zoho.com/mail/help/adminconsole/public-groups.html

When I fill out the form after clicking "Add Group" I get the error message "Group Creation Failed"

Please advise - we need this ASAP.

I have attached a screenshot. Please note we have tried this with and without a description, with more members and less. Nothing seems to work.

Thanks.