550-Please turn on SMTP Authentication in your mail client. Why?

lexcomputer

Verified User
Joined
May 20, 2017
Messages
11
When I sent mail to some domains, it returned :

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

[email protected]
host recipientdomain.com [222.222.222.222]
SMTP error from remote mail server after RCPT TO:<[email protected]>:
550-Please turn on SMTP Authentication in your mail client.
550-mail.mydomain.com [111.111.111.111]:33832 is not permitted to relay
550 through this server without authentication.
Reporting-MTA: dns; mail.mydomain.com

Action: failed
Final-Recipient: rfc822;[email protected]
Status: 5.0.0
Remote-MTA: dns; recipientdomain.com
Diagnostic-Code: smtp; 550-Please turn on SMTP Authentication in your mail client.
550-mail.mydomain.com [111.111.111.111]:33832 is not permitted to relay
550 through this server without authentication.

I set SPF correctly. Tested from several online SPF tester tools.
PRT Record is set.
MX is set correctly.
A Record for MX is set
It happened to several recipient domains. I am using the latest DirectAdmin, updated a few days ago.
How can I solve this problem?
 
Last edited:
It's not your problem if you're sending through your own mailserver. It's a problem of the recipient. Look at this:
550-mail.mydomain.com [111.111.111.111]:33832 is not permitted to relay
So this looks as if [email protected] is forwarding his mail to [email protected] creating a relay which is not allowed by mail.mydomain.com.
Or they are using 3rd party mail solutions like the Google mail app.

This often happens to me too when forum users from my hobby forum gets mail send to them and they have their mail which they registered with forwarded.

In short: Not your fault, not your problem. They or their host should fix things. ;)
 
I don't quite understand what you mean.

If you want you can also send me a pm. I'm Dutch (Nederlands) so if you are too you can use Dutch too, makes live easier.
In a pm you can use real examples. Or maybe explain better what you are trying to accomplish.
 
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