- Feb 12, 2020
- 1,082
- 55
The only way to get emails reliably to Microsoft (Outlook/Hotmail/Office365) is to consistently send high-quality emails to their IPs, and request unblocking if they block your IP.
Check the IP against blacklists (MXToolbox.com is great for that), and apply for removal from those lists.
Also ensure that you have DKIM, SPF and DMARC setup on your domain, and the Reverse DNS is setup correctly on your server.
Then, slowly ramp up your sending to Microsoft destinations. Adding something like Mail.Baby or any other SMTP relay (eg Amazon SES, SendGrid, etc), can also help as a fallback if your own IP isn't able to send to them.
Note that the providers that have Port 25 open by default are more likely to have bad IP ranges which have lower inbox delivery rates, and you'll have to work harder to show that you're a trusted sender.
Generally, it's easier to just use a SMTP provider (like Mail.Baby or Amazon SES) to deliver all emails, rather than trying to build that IP reputation.
Check the IP against blacklists (MXToolbox.com is great for that), and apply for removal from those lists.
Also ensure that you have DKIM, SPF and DMARC setup on your domain, and the Reverse DNS is setup correctly on your server.
Then, slowly ramp up your sending to Microsoft destinations. Adding something like Mail.Baby or any other SMTP relay (eg Amazon SES, SendGrid, etc), can also help as a fallback if your own IP isn't able to send to them.
Note that the providers that have Port 25 open by default are more likely to have bad IP ranges which have lower inbox delivery rates, and you'll have to work harder to show that you're a trusted sender.
Generally, it's easier to just use a SMTP provider (like Mail.Baby or Amazon SES) to deliver all emails, rather than trying to build that IP reputation.