Undelivered Mail Returned to Sender when trying to register with Hotmail account

[François Van Lerberghe]

Hello,

People with Hotmail or Outlook account cannot register to our forum. After the registration process, they don't receive the confirm email address message. Instead a message is sent from <[e-mail]>  with the subject "Undelivered Mail Returned to Sender". See below.

It seems that outlook/hotmail is blocking the mail coming from Nabble domain.
Can someone help me ?
Does someone at Nabble could do  something to cancel this blacklisting ?

Thank you.

François

This is the returned mail :
----
This is the mail system at host n3.nabble.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

<[e-mail]>: host
   hotmail-com.olc.protection.outlook.com[104.47.126.33] said: 550 5.7.1
   Unfortunately, messages from [162.255.23.22] weren't sent. Please contact
   your Internet service provider since part of their network is on our block
   list (S3140). You can also refer your provider to
   http://mail.live.com/mail/troubleshooting.aspx#errors.
   [PU1APC01FT044.eop-APC01.prod.protection.outlook.com] (in reply to MAIL
   FROM command)
Reporting-MTA: dns; n3.nabble.com
X-Postfix-Queue-ID: 912F42492561C
X-Postfix-Sender: rfc822; [e-mail]
Arrival-Date: Mon, 22 Feb 2021 06:08:15 -0700 (MST)

Final-Recipient: rfc822; [e-mail]
Original-Recipient: [e-mail]
Action: failed
Status: 5.7.1
Remote-MTA: dns; hotmail-com.olc.protection.outlook.com
Diagnostic-Code: smtp; 550 5.7.1 Unfortunately, messages from [162.255.23.22]
   weren't sent. Please contact your Internet service provider since part of
   their network is on our block list (S3140). You can also refer your
   provider to http://mail.live.com/mail/troubleshooting.aspx#errors.
   [PU1APC01FT044.eop-APC01.prod.protection.outlook.com]
...

[Israel <Nabble>]

What is the link to your forum?

[François Van Lerberghe]

http://archives-du-forum-membres.1010434.n3.nabble.com

[Israel <Nabble>]

Is it possible to remove the forum from your site?

[François Van Lerberghe]

Eventually. What do you want to do ?

[Israel <Nabble>]

We'll test it.

[François Van Lerberghe]

Hello Israel,

Sorry for the delay.
I've stopped the redirection of the nabble forum. You can now access to the forum independently.
Is it enough for you or have I to remove embedded code in the HTML page of my website ?

[François Van Lerberghe]

Ok I have completely removed the embedded code from my website. Hope I will retrieve it...
Thank you in advance

[François Van Lerberghe]

Any news about this problem ?

[François Van Lerberghe]

Hello Israel,

You are busy for sure as I don't see any answer from you. Ok, I can understand that.
I embedded again my forum in our website.
Let me say when/if you are ready to see if my problem could be fixed. It would be nice.

François

[Israel <Nabble>]

Hello François,
Sorry for the late reply. We are having problems we embedded forums. Unfortunately I were unable to reproduce the issue reported on a test site. Nabble has low priority for bug fixing for while.

[François Van Lerberghe]

Hello Israel,

Thank you for your answer.
As I can see in the error return post, joined in my first post, it's not a bug in Nabble, it's a blacklisting of Nabble dns (162.255.23.22).

"<[e-mail]>: host
   hotmail-com.olc.protection.outlook.com[104.47.126.33] said: 550 5.7.1
   Unfortunately, messages from [162.255.23.22] weren't sent. Please contact
   your Internet service provider since part of their network is on our block
   list (S3140). You can also refer your provider to
   http://mail.live.com/mail/troubleshooting.aspx#errors.
   [PU1APC01FT044.eop-APC01.prod.protection.outlook.com] (in reply to MAIL
   FROM command)
Reporting-MTA: dns; n3.nabble.com"

It seems to me that the dns "n3.nabble.com" is in a block list at Hotmail/Outlook. If I'm right, you must fix it between Hotmail/Outlook/Microsoft and Nabble.

Many customers had this problem. See this thread :
https://answers.microsoft.com/en-us/outlook_com/forum/oemail-oattach/hotmailoutlook-block-list-s3140-blocks-all-new/699f3a56-406e-4804-97e2-cbe23b9bb01c?page=1

You will find good explanations for fix the problem
- at the end of page 4 of the thread
- at https://blog.paranoidpenguin.net/2020/08/outlook-com-is-no-longer-blocking-my-mail-server/

But only Nabble can do that, not me !
It would be nice if you could do something for me about this problem.

François