There are a number of articles in the KB which may not be visible if you are not logged in to the Support Portal. 


We do have a section in the KB called "Third Party Senders" which is visible to users who are logged into the portal.


In order to log in, simply create an account by clicking the "Sign Up" button at the top right. Follow the steps to create an account and you'll be able to read more KB articles and check on the status of any ticket you may have open!