"The data you have entered already exists" when trying to create contac@mydomain.com in Zoho Mail

"The data you have entered already exists" when trying to create contac@mydomain.com in Zoho Mail

Hi,

Our domain is symsoluciones.com, Working as admin in the control panel:
When I try to add the email account " cesarmedina@symsoluciones.com" and " felixsolis@symsoluciones.com" I get the error: "The data you have entered already exists"

The accounts in mention, were created and eliminated, but I do not know continue to appear as existing.

Any ideas? Can anybody help us?

thanks!