Vista email - Error Unable to relay


  • Unable to relay
  • Email not working

Product Line

TAC Vista


  • Vista
  • SMTP


If an error "Unable to relay" is returned, this is most likely because authentication is not sent to the SMTP server.


  1. Go to Vista Server settings
  2. At the email tab set proper authentication (TAC Vista Technical Manual Chapter 3.3 explain this more in detail)
  3. You may need to consult with the IT department on site

For more information on troubleshooting sending emails from a Vista server, see Lessons Learned Article #3663.