In this case my client had subscribed to a third party website newsletter. It was a UK Government website, so one might reasonably suppose they know what they are doing. …. which turned out not to be the case.
The newsletter which was sent out quite frequently included lots of links in it to other websites. It also showed the sending domain in the message, let’s say in this case it was finance.gov.uk. So the incoming messages appear to come from the domain https://finance.gov.uk. However they were going into the recipients junk email folder. Why?
Analysis
The sender was using a third party bulk mailing service called Send Grid. Send Grid is a legitimate sending source for bulk mail, this is what they do. However in the case of finance.gov.uk they did not change their settings to tell a receiving mail server that mail may also be sent by sendgrid.com. The fix required is at the senders end which of course you have no control over. (But you could be nice and let them know, because the same may be happening everywhere.)
Solution
In this case the receivers mail settings in the server were adjusted to accept mail coming in from sendgrid.com. It was whitelisted, so even though there is an error on the sending end, with it not being configured properly, analysis of the incoming email can show you what needs to change in order to accept the message.
The whitelisting (accepting) function overrides any mail filtering going on in the hosting.
If you have access to your Hosting Control Panel, you can make these changes yourself.
Please note
If you have or are considering using an external email service, please let me know. There have been cases in the past where a client has worked with a third party to set this up and screwed up the communications from the website. You do not have to use the email services I provide, and in some cases, you may be better off using external mail service, or a combination of the two. I am quite happy to work with the third party to ensure you have a seamless transition and everything still works afterwards!
Many external consultants, only look at the problem of setting up the new system and fail to check the transition has worked from an old system to a new system. Don’t leave it wholly in their hands. They may not appreciate that the website uses email addresses too.