When you log into the SpamHero control panel, sometimes you will see this warning:

You will see this warning only when your domains current MX records are not exactly matching the recommended MX records.  To begin troubleshooting, you will first need to find out what MX records your domain are using.  You can use this website to check your MX records:

http://mxtoolbox.com
Once you reach that site, enter your domain name, and click MX Lookup:

This will show you what MX records your domain is using.  Now, take a look at what MX records we recommend.  You can do this by clicking the Settings > mail host tab, then scroll down to the bottom:

Please note, if your domain's MX records don't match, or if you are using only 1 or 2 of the recommended records, or if you have another MX record that isn't on the recommended list, then you will get this warning in the Dashboard.