5.7.1 Unable to relay error

Hi Team,

I am getting 5.7.1 Unable to relay error ,when sending email from SMTP Server.


Hope this thread help you resolve the issue.

Hi @Shilpa_Sahu

You can change the relay configuration to “authenticated users” only
Follow the Below steps:

  1. Open the Exchange System Manager;
  2. Go in Administrative Groups → Administrative group name → Server → Server name → Protocols → SMTP;
  3. Right click on Default SMTP Virtual Server → properties;
  4. Access tab → Relay button;
  5. Select “only the list below” and add your domain and\or IPs you do want to allow the relay.
  6. And finally, check the “Allow all computers which successfully authenticate to relay, regardless of the list above” checkbox.
    Refer to the link:
    Solved: Exchange SMTP Error 550 5.7.1 Unable To Relay

Or Try Like this method
Is the domain name to which the remote user sends the e-mail in your “Accepted Domains” list?
Running this cmdlet will show you the domains for which your server will accept e-mail:


yes its there