I am getting a strange error, though I may be missing something really obvious. This is the first user I have added, so it may be my error.
Our mailer is set up for SMTP, and it works just fine for everything, but a user was getting a 550 error when sending a test email to themself. I have triple checked the email address, it is entered correctly.
Is there somewhere that I have to add this email in CiviCRM in order to have tests work for them?
Using: CiviCRM 4.6.24
Attempting from: Mailings > New Mailings
Error in call to Mailing_send_test : Failed to add recipient: "EMAIL ADDRESS HERE" [SMTP: Invalid response code received from SMTP server while sending email. This is often caused by a misconfiguration in Outbound Email settings. Please verify the settings at Administer CiviCRM >> Global Settings >> Outbound Email > (SMTP). (code: 550, response: 5.1.1 : Recipient address rejected: User unknown in relay recipient table)]
Response to Jon G:
I don't think it is the server, i can go check the logs though... The test works for firstname.lastname@example.org, email@example.com, firstname.lastname@example.org, etc. It just doesn't work for one particular user.
:::::::::::: SOLVED ::::::::::::
I had to add the user to our relay. I wasn't aware that we were using a relay. :P