Troubleshooting Exchange Server Error ‘550 5.7.1 Unable to Relay’

While working on Exchange Server with MS Outlook, the users often bump across the following error message when they try to send emails outside their domain:

550 5.7.1 Unable to Relay


Error 550 occurs when emails are sent to a domain other than the user’s. This error signifies that the outgoing mail server fails to recognize the sender. This means that the users are not authenticating to the server and hence, they are not allowed to send emails. The second possible reason could be the absence of the recipient policy for that domain in the user’s department. Exchange Database (EDB) corruption is another factor that generates the above error.


The aforementioned error message can be resolved by these solutions:

Solution1: Go to the Administrative Groups in the Exchange Server Manager. Select Administrative Group Name -> Server -> Server Name -> Protocols -> SMTP. Choose Properties option by right clicking on Default SMTP Virtual Server. Choose Access tab and click on Relay to select ‘only the list below‘. Now, add the IPs you want to relay and your domain. Finally check ‘Allow all computers which successfully authenticate to relay, regardless of the list above‘.

Solution2: You can also figure out the various Exchange Server errors you encounter in the application event log and look for their resolve on-line.

If the Exchange Error 550 is due to the result of database corruption, it can be repaired using Microsoft inbuilt utility Eseutil. In case after using the ESEUTIL utility the database is not repaired due to severe corruption then you need to devoir a third party Exchange Server Database recovery tool. Among the copious EDB repair tools available in the market, a reliable solution is “Stellar Phoenix Mailbox Exchange Server Recovery”.


Exchange Server Repair/Recover Utility. Click above to Install. Try Free Demo!!

This powerful software is able to recover all the data from the corrupt EDB file in 3 simple steps:

  • Select the EDB file that you want to repair.
  • Scan- Run the Quick/Extensive Scan to scan the user mailboxes and their items.
  • Recover- Once you have selected the desired items for recovery, you can save the recovered files at a specified location.

Not only does the Exchange Repair software offer a preview of the user mailbox items such as emails, attachments, contacts, calendar, tasks, To-do lists and journals it is compatible with all the major versions of MS Exchange Server, namely, 5.5, 2000, 2003, 2007 and 2010.

A completely risk-free utility, Stellar Phoenix Mailbox Exchange Recovery restores your vital emails and user data without affecting the original file formatting. A complete user guide to install and run the software comes along with it.  Visit to Know more –

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