Getting email to a hotmail account rejected

[#1]

Over the last week or so if I send an email to a hotmail account it gets a delivery failure saying the plusnet server is on a block list. Anyone else seen this?

Reporting-MTA: dns; avasout-peh-001 [212.159.14.17]

Final-recipient: rfc822; XXXXXXX@hotmail.co.uk
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 (S3140).

Anyone else seeing this?

[#2]

Apologies. This seems to already been covered in another thread

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

[#3]

Yes - we have just had an email rejected by hotmail. We have migrated to Greenby - have you?

The error details were...

Reporting-MTA: dns; gateway1.enmail.co
X-Postfix-Queue-ID: 942C74644D
X-Postfix-Sender: rfc822; @<name>@<account>.f9.co.uk
Arrival-Date: Mon,  9 Feb 2026 14:15:26 +0000 (UTC)

Final-Recipient: rfc822; <recipient><@hotmail.co.uk
Original-Recipient: rfc822;<recipient>@hotmail.co.uk
Action: failed
Status: 5.7.1
Remote-MTA: dns; eur.olc.protection.outlook.com
Diagnostic-Code: smtp; 550 5.7.1 Service unavailable, Helo domain is listed in
    Spamhaus. To request removal from this list see
    https://www.spamhaus.org/query/lookup/ (S8001)
    [AMS0EPF000001B6.eurprd05.prod.outlook.com 2026-02-09T14:15:27.638Z
    08DE61570A027AF7]

I have raised a ticket on Greenby for this.

[#4]

Greenby asked me for my server details (unchanged from pre-migration), then asked me to send via webmail to prove it was not my settings ... and it was rejected by hotmail in exactly the same way. What a suprise!

[#5]

Greenby said they were aware, and working on it, and a resend at 17:50 was delivered ok.