I got the message " User already exist" and create invitacion

I got the message " User already exist" and create invitacion

Hi support,

Please help me to resolve this issue, i'm trying to create email coordinadora.sig@transportadorasanpablo.com  
from super account administrador@ transportadorasanpablo.com  , but it was show me , account   already exist, 
and create a invitacion.

Thanks!