Invitation in Zoho campaign

Invitation in Zoho campaign

Hi,

I am trying to invite a person of our company into Zoho Campaign by using the same email address that he uses in Zoho CRM and I can't, this message appears:  This email address has been already used in some other organization. So you cannot add/invite this user.

I don't want to invite him with a different address because it will become confusing between the CRM and Campaign...

How can I do ?

Thank you