One of the ways spam filtering systems determine if an email is spam is to check the email header to see if the server sending the email is an authorized sender. This is done by checking the domain from the email address of the person sending the email (the FROM address) and seeing if that domain has given permission to ContentMX to send email on its behalf. For instance, if you are sending an email from firstname.lastname@example.org, the spam filter will check the DNS records of mycompany.com to see if it authorizes email to be sent from the ContentMX email servers.
To authorize ContentMX as a sender, you (or your IT administrator) should add ContentMX to the SPF setting in your DNS. This is done by adding or modifying the TXT record containing the SPF information. You will be adding “include:contentmx.net” to this record.
For example, if your SPF record looks like this:
v=spf1 include:spf.protection.outlook.com ~all
you would modify it to look like this:
v=spf1 include:spf.protection.outlook.com include:contentmx.net ~all
Once this change is made, it may take a little time for it to replicate across the Internet.
If you plan to make the change to your DNS yourself, Here are some links to instructions for editing DNS records with common domain providers.
GoDaddy: Add an SPF Record
Google Domains: DNS Basics
Hostgator: Manage DNS records
Network Solutions: Edit DNS Record
Squarespace: Advanced DNS Settings