Bouncing email ...

[#1]

Good morning all,

What should we or can we, do about this please (as far as possible any identifiable information has been removed).: I don't think I can get support for this problem other than by sending you this via the Forum?

[See final lines for end of message].

* STARTS ********************************************************************************************************* "

Subject	Mail delivery failed: returning message to sender
From	<>
To	[email protected]
Date	Fri 12:23

This is an automatically generated Delivery Status Notification.      
Delivery to the following recipients failed permanently:
   * c**********[email protected]
Reason: A message that you sent to the following recipient could not be delivered due to a permanent error. ** The remote server ?? responded with: ** c************[email protected] ??:?? This message was created automatically by mail delivery software on the server .Reporting-MTA: dns; avasout-ptp-001 [84.93.230.227]
Received-From-MTA: dns; [10.0.0.50] [81.174.172.173]
Arrival-Date: Fri, 17 Jul 2026 12:23:43 +0100
Final-recipient: rfc822; c**********[email protected]
Diagnostic-Code: smtp; 550 5.7.1 Unfortunately, messages from [84.93.230.227] 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 http://mail.live.com/mail/troubleshooting.aspx#errors. [Name=Protocol Filter Agent][AGT=PFA][MxId=11BDC649DA5BE69E] [SJ5PEPF000001E8.namprd05.prod.outlook.com 2026-07-17T11:23:45.104Z 08DEE324EE5746BA]

Last-attempt-Date: Fri, 17 Jul 2026 12:23:45 +0100

Received: from [10.0.0.50] ([81.174.172.173])
    by smtp with ESMTPA
    id kgfOwyy2PEcnnkgfPwRlrc; Fri, 17 Jul 2026 12:23:43 +0100
X-CM-Score: 0.00
X-CNFS-Analysis: v=2.4 cv=JLGYsNKb c=1 sm=1 tr=0 ts=6a5a10bf
 a=eke30a/iN1tYvWdNrIz//A==:117 a=eke30a/iN1tYvWdNrIz//A==:17 a=UqCG9HQmAAAA:8
 a=0efqlMZrAAAA:8 a=scaa_ZM04Dn-tBqT5B4A:9 a=CjuIK1q_8ugA:10 a=SSmOFEACAAAA:8
 a=H8RKlYOkfK658NP_Og0A:9 a=XPzG_bKNWtY-6ikO:21 a=_W_S_7VecoQA:10
 a=19DidLf9i2jSDKuVIpRh:22
X-AUTH: KASpencer@:2500
From: [email protected]
To: Clive Briggs <c**********[email protected]>
Date: Fri, 17 Jul 2026 12:23:41 +0100
MIME-Version: 1.0
Subject: Re: O****n
Message-ID: <[email protected]>
Priority: normal
In-reply-to: <PAVPR02MB9330FDF5595CF664F37ED38DD7C62@PAVPR02MB9330.eurprd02.prod.outlook.com>
References: <PAVPR02MB9330FDF5595CF664F37ED38DD7C62@PAVPR02MB9330.eurprd02.prod.outlook.com>
X-mailer: Pegasus Mail for Windows (4.80.1028)
Content-type: Multipart/Alternative; boundary="Alt-Boundary-3520.11437093"
X-CMAE-Envelope: MS4xfGqu8BvHXgWncpbAujoTE2p5mp9QdT4+BZyM2VoyebPmRKo25ib3waFTlIxwiKgzyH8vFXRVWdtRUhUun7eiNj1Ukhjfdyvv4gSuWGwJnIpD10FdkDOR
 Z3K76DvRxFNFUIxA9lczNnjlRWens/kwkrGTybzqOlS4RQT2CWw9S7JSe+3teJiOdl5YYQv8jQT4RRk8BbbzWK/jGCUWUoZHbzQ=

Subject	Re: O****n
From	[email protected]
To	C****e B*****s
Date	Fri 12:23
Priority

**SENT REPLY**

Thanks, D******e ...

That's fine!

Best wishes,

Ken

--

**ORIGINAL MESSAGE**

From: C**********s <c**********[email protected]>

To: "[email protected]" <[email protected]>

Date sent: Fri, 17 Jul 2026 11:04:48 +0000

Subject: Organ

Hi Kenneth

W**************************************************************************************e

Thanks

D****e

* ENDS ************************************************************************************************************ "

It seems as though Outlook has issues with PlusNet.

Thanks,

Kenneth Spencer

[#2]

Diagnostic-Code: smtp; 550 5.7.1 Unfortunately, messages from [84.93.230.227] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150).

This occurred when sending via Plusnet SMTP : relay,plus.net or possibly via Plusnet webmail

if your email has migrated to Greenby try using Greenby SMTP relay.force9.net in place of : relay.plus.net
or try sending via Greenby webmail : https://webmail.greenby.com

[#3]

You’re probably ahead of me with this, using your own custom email domain through PlusNet and all. A quick DNS MX record check says there’s no DMARC policy published for that domain, which is one signal that Outlook/Microsoft would use to be circumspect, but which would be more likely to end up in the suspected spam folder, not blocked entirely.

The reason for refusal given by Outlook/Microsoft to Greenby/PlusNet is “…part of their network is on our block list..” but they’re not saying which part.

Perhaps check the Greenby/PlusNet guidance on custom domains for DMARC as a starting point? As the Greenby domain is already included in the custom domain’s SPF records, I assume that’s already up to date. But maybe check that too. But if the real reason is that Microsoft has fallen out with all of the custom managed domains through Greenby, then it might be resolved in hours or days.

[#4]

The blocked server is Plusnet hosted : avasout-ptp-001.plus.net  [84.93.230.227]

This email was not dispatched via a Greenby server.

[#5]

The reply #2 from @PhilipHeyes is better than mine (3). When I posted mine, his better reply was not visible to me… I should have refreshed first…)

[#6]

---

@PhilipHeyes wrote:

The blocked server is Plusnet hosted : avasout-ptp-001.plus.net  [84.93.230.227]

---

https://mxtoolbox.com/SuperTool.aspx#

blacklist:avasout-ptp-001.plus.net 
red icon We notice you are on a blacklist. 
Checking avasout-ptp-001.plus.net which resolves to 84.93.230.227 against 68 known blacklists...
Listed 1 times with 1 timeouts
                        Blacklist         Reason   
Status Problem LISTED:  Anonmails DNSBL:  84.93.230.227 was listed: 

Spam?

https://anonmails.de/dnsbl.php

Please enter a valid IP-address or hostname. 84.93.230.227
Blacklist Status
The IP 84.93.230.227 is listed in spam.dnsbl.anonmails.de since Sat, 14 Mar 26 08:31:44 +0100 because of sending spam.
The entry will be removed automatically from the blacklist in the next 24 hours after the last spam email has been detected.
Spam hits: 27    

[#7]

Possibilities:

1. avasout-ptp-001.plus.net not secure and being used to send Spam via SMTP. (Would have thought this unlikely by now).
2. Genuine Plusnet users sending out Spam via their account.
3. Plusnet users' account information compromised and stolen credentials used to send Spam via PN host.
4. Plusnet users' PC's compromised and installed Bots sending Spam.

DNSBL Removal Request (anonmails.de)

"The IP address will be removed soon."

We shall see! 😉

[#8]

Chapter & verse on this is at :

https://community.plus.net/t5/Email/Hotmail-rejecting-mail-from-PN-Diagnostic-Code-smtp-550-5-7-1/td...