Microsoft Silently Dropping Emails – a Sad but True Story
 

https://www.nerd-quickies.net/2020/1...ut-true-story/

btw, I did meet this issue for myself. So I don't use MS's email serivce.

There is something arbitrary as to which emails are blocked by Microsoft. My business has a Wordpress website that daily sends me routine notification emails using our own domain. Even though these emails are identical and routine, some of them are put into Junk by Microsoft while most are not. Sometimes identical, routine emails sent on the same day go into Junk while most arrive in my Inbox. There appears to be no reason why one email should be rejected and the other is not. I have been able to do nothing about it and instead must check my Junk email folder frequently for the many legitimate emails that arrive there. The same thing happens to emails from other organizations, including major national and international companies. Most of their email arrives in the Inbox, some does not.

I first noticed this while working at HostGator. Routinely customers would open tickets about emails disappearing into thin air while targeting Outlook/Hotmail. In almost all cases I was able to replicate it from their domains.

Naturally, I started to try to narrow down the cause to find out if it could be IP reputation, domain reputation, or content. If I could send an email from their domain that was a personal email from me to myself, I'd pretty well rule out content. It would persist, so ruled out. I'd bring in one of my own test domains and add it to their VPS (where the customer had a VPS and therefore a dedicated IP for mailing) and send myself an email from that domain, I'd get it in my inbox. So that ruled out IP reputation. In my tests, domain reputation seemed to be my conclusion.

That said, it wasn't a large enough sample size to say it's the only reason. A customer of mine at MXroute once noticed the same behavior and they cleared it up by changing their Content-Type header. I can't recall which header they'd set and what they changed it to, but the client was someone I'd trust.

What basically is needed is a class lawsuit against MS.

For this reason we use only Fastmail or Gmail.

Even Namecheap Private Email while reasonably priced is an absolute joke with deliverability issues and an outright block on email deliverability by e.g. mimecast etc.

@Jarland interesting post, merits a further look?

We did consider MXroute but went with FM monthly billing basically. Thanks.

Its sad when they do this.......