@vivia @slomo in my experience, Microsoft is better than Gmail. But they both gatekeep email standards, so I understand. Most of my rejections come from Google.

It could be your IP was previously used by spammers. Related, on my last hosting service, Bing insisted my website hosted malware because the previous person on the server in fact hosted malware. It took almost a year to get re listed and cleared as “safe.” 🥲

@vivia @slomo

I ended up having to create a Microsoft account and submitting a ticket to Bing Webmaster Support. I got canned answers, but could see when they would relist the site. It would constantly fall out Bing's index though.

I did a lot of digging into the history of my site's previous IP address. What ultimately ended the repeated de-listing in Bing was indeed switching hosts, though I'm not sure it was host-related. But I had my own issues with them, so was happy to leave.

@vivia @slomo I never figured out what the real issue was though, as they keep it a closely guarded secret.

Given what I learned, it was the IP address. I don't know if you could ask your host to reallocate your IP block, or switch servers within the same host to see if that alleviates the issue.

Edit: Wanted to add my current provider has issues with their site coming up in Bing's index, but I haven't had the same issues.

@vivia @slomo I know the struggle, I really do. I'm so sorry. :(

You probably have most of this list down:

- Check MX records
- Double check you're not a relay
- If other users have email on your server, ensure they're not mass sending messages
- Consider connecting to Bing Webmaster Tools... yes I know :/ (it can tell you if you've been flagged as malware via Bing/Microsoft)
- Check trend micro security center and others (virustotal)
- Change DMARC to quarantine
- Make sure DNSSEC is enabled