Instead of Adding a new user it just goes into invitation list

Instead of Adding a new user it just goes into invitation list

Hello Experts,

I am trying to add a user or email address swps@khoomyanmar.com. The domain is now pointing to zoho and all other account creation work fine except for this particular account. Whenever I try to add the email address instead of adding it just goes to invitation list. Appreciated if someone could help me out. Thanks.