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Issue Undelivered Mail Returned to Sender

brainlabs

New Pleskian
Server operating system version
CentOS Linux 7.9.2009 (Core)
Plesk version and microupdate number
Plesk Obsidian V 18.0.48, update on 13.12.2022 15:04
Hello, have a nice day.
I am a new member to the forum.

I've read the threads on the forum, but to no avail.

We have been grappling with this error for a while. When our customers send mail to addresses such as @gmail.com or @hotmail.com, they get an "Undelivered Mail Returned to Sender" error.

We have changed IP addresses twice, I believe all our settings are correct.

I would be very happy if you share your valuable information on how to solve the problem.

Our IP Address 45.141.149.110
Thanks in advance. Happy New Year to all :)
 
Your server's IP is listed with many blacklists. Check it here:

Further, GMail und Hotmail are using their own. For GMail you cannot get access to their blacklists, but for Microsoft systems you can participate in the SNDS program (for free) to get an insight what MS thinks about mail that is coming from your server:
Sign in to your Microsoft account
 
Hi Everyone,

Before deciding to write you here, I tried all that I knew how to fix situations when sending emails from the host domain to Outlook.com or Hotmail.com when the email was not delivered. And in that case what needs to be set or configured to improve case scenarios.

But the problem I have with Plesk I don't know what is exactly the problem.

This is the mail system at host hosting.myserver.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system
<[email protected]>: host
outlook-com.olc.protection.outlook.com[104.47.58.33] said: 550 5.7.1
Unfortunately, messages from [xxx.xxx.xxx.xxx] weren't sent. Please contact
your Internet service provider since part of their network is on our block
list (S3150). You can also refer your provider to
[DM6NAM10FT008.eop-nam10.prod.protection.outlook.com
2023-03-04T13:32:51.520Z 08DB1C6481C5A10B] (in reply to MAIL FROM command)
Reporting-MTA: dns; hosting.myserver.com
X-Postfix-Queue-ID: 4C77E201632
X-Postfix-Sender: rfc822; [email protected]
Arrival-Date: Sat, 4 Mar 2023 14:32:50 +0100 (CET)

Final-Recipient: rfc822; [email protected]
Original-Recipient: rfc822;[email protected]
Action: failed
Status: 5.7.1
Remote-MTA: dns; outlook-com.olc.protection.outlook.com
Diagnostic-Code: smtp; 550 5.7.1 Unfortunately, messages from [xxx.xxx.xxx.xxx]
weren't sent. Please contact your Internet service provider since part of
their network is on our block list (S3150). You can also refer your
provider to Troubleshooting.
[DM6NAM10FT008.eop-nam10.prod.protection.outlook.com
2023-03-04T13:32:51.520Z 08DB1C6481C5A10B]

IP Address is not on any blacklist, Domain Health Report from MX Lookup Tool - Check your DNS MX Records online - MxToolbox myserver.com does not have any trouble or user domain domainuserinplesk..com all is fine.

To make the problem even stranger, when I test and send an email from domainuserinplesk..com to any user who has an email service based on Office365 that user received an email every time successfully.


If anyone has an idea what can be a problem with Plesk or what needs to reconfigure.

Thank you,
 
Microsoft has their own blocklists that cannot be checked publicly unless you take part in there SNDS program. You can check your IP address here Sign in to your Microsoft account and ask to be removed from their blocklist here Sign in to your account

Hi Peter,

I do that in the process configuration server before putting online in the product and, in SNDS - Access Control IP address has the status Normal and No data for specified IPs.

When I write ticket support on Microsoft here I get information from Microsoft that the IP address is not blocked from his side and everything is normal.

That is the reason why I a write you here for help if anyone has this weird situation.

Thank you,
 
The IP address might not be blocked, but the subnet must be blocked. Else their servers would not return the message "Please contact your Internet service provider since part of their network is on our block list (S3150)." But even in that situation so far my experience was that they can whitelist single addresses.
 
I had a similar issue when I first switched to Linode. There's a few things you would want to do.

First make sure you refer to Outlook.com Postmaster as that will provide you with a lot of details.

I would also recommend signing up for the Junk Mail Reporting Service over at Sign in to your Microsoft account (this is outlined in the first link).

Once you've done all that and the issue is still not resolved then put in a ticket with Microsoft via Sign in to your account and state that you've followed the troubleshooting guide outlined in https://sendersupport.olc.protection.outlook.com/pm/troubleshooting.aspx but when sending emails to outlook.com email addresses you are getting a bounce back of "
smtp; 550 5.7.1 Unfortunately, messages from [xxx.xxx.xxx.xxx]
weren't sent. Please contact your Internet service provider since part of
their network is on our block list (S3150). You can also refer your
provider to Troubleshooting."
(make sure you include this bit including your actual IP address of the the outgoing email server).

That's what I did and they've fixed it right up for me.
 
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