Users from Zoho Desk cannot create tickets from portal

I recently created my help desk using zoho desk. So i tested it creating a contact and adding as end-user. After that the user could create tickets by email or by Help center. But later, I clicked on delete that user (from settings, help center, users). And after i recreated the user with the same email again. Then I tried one more time to create a ticket from email: sucess. And as well to create a ticket from the help center: fail. I can't do it anymore. After press "send" it appears a message : The request can not be processed or something like that. Please I need help! (It's not a problem with the visibility of the department )