Usable to add user to my Zoho Campaigns

Usable to add user to my Zoho Campaigns

Hi, I'm trying to add manuela[at]densitymedia[dot]com to my organization Zoho Campaign account but I'm getting this error:

"This user is a member of another organization of Zoho Campaigns. So you cannot add this user to your organization."

Can you please help me?

Kindest regard,

Gabriele