Click in the yellow exclamation mark button to check if there are any errors. If your campaign contains any external domains, a message will show up on the top right corner of your screen, showing a short explanation on what external domains are present in your campaign – they can be in the “Design content”, “Plain Text Content” or in the HTML Source.
After the errors are shown, search for them inside the corresponding area (“Design content”, “Plain Text Content” or in the HTML Source). After you find the detected errors, just remove or change them.
Bear in mind that when the external domain is detected in the HTML, many times they are inside fields such as “title=” and they will have to be removed. Bear in mind that a correctly inserted domain is inside “href=” or “src=” fields. All the other fields can’t contain external domains.
After you have performed the changes, please repeat Step 1 to check if there are any other errors. Do not forget to save and submit your campaign.