Invite my mgr to ZOHO Campaigns it give an error “ this email address has already been used.....

Invite my mgr to ZOHO Campaigns it give an error “ this email address has already been used.....

When I try to invite my mgr to ZOHO Campaigns as a user  it give an error “ this email address has already been used in some other organization, you cannot add this user” . How do I add her to my organization? Can she be a member of multiple ZOHO Campaign organizations?