Problem Reported: 

User got the email from the email ID of the organization which is already deleted.

 

Observations:

The sender Email ID(Non-existent/Deleted) is a alias of user “email ID”(Existent). The alias ID can be used for the authentication while sending the mail and it can also be configured in applications.

 

Solution:

The alias ID authentication can not be removed, if you don’t want the alias ID you can remove it using the Admin Panel console.