SMTP error from remote mail server after RCPT

0306x

Registered
Jun 3, 2019
4
1
3
poland
cPanel Access Level
Root Administrator
When someone fill the form on my page with email account in example.net they don't recieve confirmation email from my website. There is only problem with email delivery to example.net email accounts. I contact them already and there is no problem with my email blaclisted on they database.

Error I get:
Code:
>> 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 mx.poczta.example.net [1] [213.180.xxx.xxx]
>> SMTP error from remote mail server after RCPT
>> TO:<[email protected]>:
>> 550 5.1.1 <[email protected]>: Recipient address rejected:
>> User unknown
>>
>> Reporting-MTA: dns; clients.example.org [2]
>>
>> Action: failed
>> Final-Recipient: rfc822;[email protected]
>> Status: 5.0.0
>> Remote-MTA: dns; mx.poczta.example.net [1]
>> Diagnostic-Code: smtp; 550 5.1.1 <[email protected]>: Recipient
>> address rejected: User unknown
my domain example.com, email [email protected]
I tried to get help from few people already but no success for now.

I have access to WHM and Cpanel.
And there is two more domains on same vps. One of them have same problem with email and another one dont have this problem.
 

0306x

Registered
Jun 3, 2019
4
1
3
poland
cPanel Access Level
Root Administrator
the onet support sended me this info:

host clients.example.org
Host clients.example.org not found: 3(NXDOMAIN)

anybody can help? - Removed -
 
Last edited by a moderator:

cPanelMichael

Technical Support Community Manager
Staff member
Apr 11, 2011
47,911
2,234
363
cPanel Access Level
DataCenter Provider
Twitter
Hello @0306x,

The error message in the output you shared indicates one of the following:

1. The email account does not exist under the Email Accounts interface in cPanel.
2. The domain associated with the email account does not resolve to the cPanel & WHM server.

Is the affected subdomain created as it's own cPanel account, or is it added as an addon domain to an existing cPanel account?

Thank you.
 

0306x

Registered
Jun 3, 2019
4
1
3
poland
cPanel Access Level
Root Administrator
1. Email account exist - and when I try send the same email like my script but manually from this same mailbox - this email still can't be delivered to email accounts on domain example.com
2. The affected domain is created as it's own cpanel account
 
Last edited by a moderator:

cPanelMichael

Technical Support Community Manager
Staff member
Apr 11, 2011
47,911
2,234
363
cPanel Access Level
DataCenter Provider
Twitter
Hello,

To update, here's a summary of the response sent by one of our Technical Analysts:

The server hosting mail for - Removed - is not accepting connections from you server to port 25.

You will need to contact the administrator for the remote mail server and provide them the information showing that their SMTP port is filtered by a firewall blocking your server's connections and in turn not allowing mail from your server.
Thank you.
 
Last edited by a moderator: