Server Fault is a question and answer site for system and network administrators. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I have developed on application for sending email. I have Specified SMTP address, credentials, and I am using Windows Server 2008, IIS 7.

I am getting this error:

Mailbox unavailable. The server response was: 5.7.1 Unable to relay for

To fix it you have to configure relay restrictions in the IIS admin.

But where this option in IIS Server 7?

share|improve this question

migrated from May 26 '11 at 0:34

This question came from our site for professional and enthusiast programmers.

To configure relay restrictions in IIS admin follow below mentioned steps

  1. Go to “Default SMTP Virtual Server” in IIS and then go to properties

  2. Select tab “Access”

  3. Select last Option "Relay Restriction" by clicking the "Realy" button

a new window will pop up

  1. Select the appropriate radio button and add IP addresses accordingly
share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.