Since you use a spam filter and Microsoft Exchange, we recommend you begin by whitelisting your email header in Exchange. For more information, see our How to Whitelist by Email Headers in Microsoft 365 or Microsoft Exchange 2016 article.

After you've whitelisted your mail server, you'll need to whitelist your spam filter. Click Next below for more information.

Note: If you would like to set up a smart host connection with Exchange, contact our support team .