This looks like it might be due to Microsoft's servers enforcing Sender Policy Framekwork (SPF), where the recipient server checks with the originator domain to validate that the message came from an approved server. As you're relaying (via Zen), this check is failing as Zen is unlikely to be a valid originator of Yahoo emails. I used to have the same problems with my own email when I used to relay everything for my domain on to my ISP's mail server, and some - but by no means all - mail got bounced.
See https://en.wikipedia.org/wiki/Sender_Policy_Framework
Cheers, Simon
On 07/12/16 08:53, Nev Young wrote:
Hi, Can any one offer advice about a problem I've been having with email for a few months now? I suspect it has something to do with increased security at host mx4.hotmail.com but I can not confirm this. The problem (in brief) I host a number of websites. Each of these has a "contacts" page where any one may send an email. The page contains the following fields: 1 a drop down box to select the recipient (e.g. secretary, chair, treasurer, events co-ordinator, etc.) 2 a text field for the sender's own email address 3 a free text field.
This prevents the sender knowing the email address of the recipient and sends an email with: To: = the recipients real email address From: = the sender's own email address Subject: = "website contact" and the body containing the free text stripped of any HTML.
All of the above works fine for all sender addresses and recipient addresses *except* when the sender is <sender>@yahoo.co.uk and the recipient is <recipient>@live.co.uk which results in a failed to deliver message which contains: A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: <recipient>@live.co.uk SMTP error from remote mail server after end of data: host mx4.hotmail.com [65.55.37.120]: 550 5.7.0 (COL004-MC4F7) Unfortunately, messages from (212.23.1.5) on behalf of (yahoo.co.uk) could not be delivered due to domain owner policy restrictions. ------ This is a copy of the message, including all the headers. ------
Meanwhile a copy of the email sent at the same time to me as site administrator works fine and is delivered.
65.55.37.120 is microsoft 212.23.1.5 is Zen internet (my isp). obviously <sender> and <recipient> have replaced real email names.
Any ideas what I need to change to make hotmail accept these emails again. Or do I just have to wait it out?
Nev
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