What are your results from:
Newsletters spam test by mail-tester.com
Secure Email
In the mail settings on one of your domains, are the following enabled?:
- SSL/TLS certificate for webmail
- Use DKIM spam protection system for outgoing mail
Lastly, did you contact Microsoft about this? In my case the IP adress i use was blacklisted, propably by the previous owner (not sure)
Newsletters spam test by mail-tester.com
Secure Email
Reverse IP Lookup - MxToolbox
mxtoolbox.com
In the mail settings on one of your domains, are the following enabled?:
- SSL/TLS certificate for webmail
- Use DKIM spam protection system for outgoing mail
Lastly, did you contact Microsoft about this? In my case the IP adress i use was blacklisted, propably by the previous owner (not sure)