SOBS email and Microsoft / Hotmail

Mar 15, 2018

Email is a conundrum.

Pros: Being able to send messages, documents, images, video, and links to everything else.  Virtually instantaneous all around the world.  Able to message a group of friends.

Cons: SPAM, SPAM, SPAM, and anti-SPAM nets.

One of our servers has been blocked by Hotmail – so parents with hotmail email addresses won’t be getting their interview bookings via email for a week or so.  I know this can be frustrating, for the parent, you and me!  We get messages bouncing like (names have been changed):

 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:
    host []
    SMTP error from remote mail server after pipelined MAIL FROM:<> SIZE=2330:
    550 5.7.1 Unfortunately, messages from [] weren't sent. Please contact your Internet service provider since part of their network is on our block list (AS3140). You can also refer your provider to []


I have sent them the appropriate message in the hope that somebody will correct the problem.  However, this can take a few days or a few weeks – I have never ever heard back from them that they have reacted to one of these messages, so I don’t know exactly what happens or when.

There are of course security measures we have put in place.  We implement a TLS certificate that verifies our identity.  We also implement an SPF record to verify ourselves to other mail systems.  Clearly hotmail are ignoring these efforts.