First of all, we need to verify that the Sender ID, DomainKey, and self-control settings are configured so that your emails sent via our tool get authorized. These settings are related with the DNS server of your domain. If you already have configured them, you need to check the “Authenticate the campaign” option when you create a new campaign.
You also need to keep an eye on the anti-spam record that your campaign received. In the 4th step of creating campaign, you will have your record displayed. Bear in mind that the anti-spam score should be below 5.0 in order to deliver your emails to the inbox.
Also take note of the words that you use in the subject of your campaign. Do not only use capital letters and use these words reasonably: offer, promotion, discount, online courses, free, must see, etc.