Problem

Last week I was testing the IMAP/SMTP connection of my Exchange 2013. Unexpectedly Outlook returned the following error:

Exchange - SMTP error 550 5.7.1 Client does not have permissions to send as this sender

The message does not appear completely but seems to be “550 5.7.1 Client does not have permissions to send as this sender”. Obviously the user does have the permissions (the user was the owner of the mailbox itself).

Resolution

Thanks to… http://sanjaysingh11.blogspot.com.es/2013/12/550-571-client-does-not-have.html I got this problem solved by configuring this permission:

Run AdsiEdit and select the following path:
Configuration – Services – Microsoft Exchange – <MY_ORG_NAME> – Administrative Groups – Exchange Administrative Group – Servers – <MY_SERVER_NAME> – Protocols – SMTP Receive Connectors:

Exchange - SMTP error 550 5.7.1 Client does not have permissions to send as this sender

Properties of the “Client Proxy <MY_SERVER_NAME>” receive connector, “Security” tab and grant the “Accept Authoritative Domain Sender”  allow permission for the “Authenticated users”.

Exchange - SMTP error 550 5.7.1 Client does not have permissions to send as this sender


Dont forget to grant it for each of your servers.

Finally I checked the problem was fixed:

Exchange - SMTP error 550 5.7.1 Client does not have permissions to send as this sender

If you also get errors configuring the IMAP service, check my post:
Exchange 2013 – IMAP NTLM authentication error