Error message "550 5.7.1 Connection refused - blocked by Validity"

[#1]

@Tykebike 

If your email service has been migrated, changing passwords in the PLSUNET user portal is not going to get you anywhere.  You need to manage your email service here - greenby.com

If this is a secondary email address for which you are having issues, then at the time of writing there are issues using the Plusnet webmail web page: login with an email address is not working - use account+mailbox as the user name or use the native Greenby webmail service - webmail.greenby.com

[#2]

How would I know if my email has been migrated as I've had no indication that it is immenent.

[#3]

Force9 is well into the migration programme, however if you have a hosted domain name with the account, then you will not yet be on the schedule.

[#4]

If your portal profile details are correct, you have been migrated. 

[#5]

Thanks.

I'm still not receiving any emails on my username@trutta.f9.co.uk so I don't know whether I have received an email from Greenby or not. The  last sync date was December 3rd.

I can log into the Plusnet Portal successfully but not to webmail on either the Plusnet or Greenby sites. On the Greenby site I have tried using my full email address and the password I use to access  the Plusnet Portal but without success.

I have tried contacting the Plusnet help but when humans tried to contact me I have been out or my phone has been somewhere else. I will try again later this afternoon.

[#6]

Hello,

I’m unable to send emails from my Totalise account to Hotmail/Outlook addresses. The bounce message says:

550 5.7.1 Unfortunately, messages from [IP address] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150).
More info: http://mail.live.com/mail/troubleshooting.aspx#errors

Microsoft’s IP Delist Portal confirms my IP isn’t blocked, so it seems part of the Plusnet/Totalise network is on Microsoft’s block list. Can Plusnet investigate and request removal from Microsoft?

Can you help me please and get this working again?

Simon...

[#7]

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@Townman wrote:

It is on the SU escalation list.

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It looks like nothing has changed since I started this topic as my latest message to an outlook.com address has bounced with:

Final-recipient: rfc822; [correctNameHere]@outlook.com
Diagnostic-Code: smtp; 550 5.7.1 Unfortunately, messages from [212.159.14.17] 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=11BC67F2CBCD4F37] [DB1PEPF0003922E.eurprd03.prod.outlook.com 2025-12-05T14:30:18.324Z 08DE33F9661525F7]

Last-attempt-Date: Fri, 05 Dec 2025 14:30:18 +0000

[#8]

@Townman @MisterW @plusnettony Any chance that us mere mortal users can be given a clue as to when this block will be removed?

My latest out going message went TO three addresses:

• one @gmail - no bounce
• one @live - instant bounce
• one @outlook - instant bounce

Both of the bounces were as already reported:

Diagnostic-Code: smtp; 550 5.7.1 Unfortunately, messages from [212.159.14.17] 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=11BC68068772BB1F] [BL6PEPF0001AB4F.namprd04.prod.outlook.com 2025-12-05T15:49:20.944Z 08DE340343E16D31]

Last-attempt-Date: Fri, 05 Dec 2025 15:49:20 +0000

[#9]

Would it be useful if a moderator could merge this strand with the other three SMTP 550 5.7.1 error strands listed by @Townman in post #2 ?  

In the absence of any progress information from Plusnet at least we users would have fewer places to search while waiting for news of a solution to the problem.

[#10]

Yesterday evening I sent an email that included several Microsoft-related addresses (i.e. outlook, live, hotmail). I thought all was well but over 24 hours later all the MS ones have been rejected saying that avasout-ptp-002 [84.93.230.235] is block listed.

The failure message includes: Arrival-Date: Fri, 05 Dec 2025 18:18:51 +0000 and Last-attempt-Date: Sat, 06 Dec 2025 18:51:04 +0000

For me, this is a totally new level of frustration - what is going on?

[#11]

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@abitpedantic wrote:

...what is going on?

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The bounce explains what is going on, MS have blcklisted part of the PN network.

What is lacking, again, is any communication from PN staff / Superusers about why this block has persisted for so long.

Please, please, please @Townman @MisterW @plusnettony @dave give us an update on how long it will be before this gets resolved.

[#12]

I'm afraid we (the SUs) dont have any updates. All we know is that the business IS aware of the problem and is actively persuing a resolution. My guess is that interfacing with Microsoft is tedious and slow...

[#13]

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@MisterW wrote:

...My guess is that interfacing with Microsoft is tedious and slow...

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Thank you, it's not great news but at least it is an update.

Your guess sounds reasonable, after all it took MS four months to fix the authentication problem that appeared last June.

On the principle that, "It's the squeaky wheel that gets the grease." I hope that PN are pestering MS daily about this problem.  I suspect they're not though, too many other demands on their time with the problems arising from the migration process.

Deep sigh.

[#14]

@stuck 

By "what is going on", I was referring to the fact that the bounce happened over 24 hours after the email was sent, I've never experienced such a lag before and it's very disruptive.

@MisterW

Does it imply, for example, that Plusnet now keep on trying to send a failed message using different avasout servers or that it can now take 24 hours to get a definitive rejection from Microsoft or what?

[#15]

Does it imply, for example, that Plusnet now keep on trying to send a failed message using different avasout servers or that it can now take 24 hours to get a definitive rejection from Microsoft or what?

It depends entirely on excatly what error code Microsoft return when receiving the email. If they return one of the 4xx (Transient error codes) then the Plusnet servers will back off and retry later. Only on receiving a 5xx (permanent error) or having retried for too long (days!) will the servers return a rejection to you