Sidebar

New user here.  I have created a newsletter in CC.  I am using the system's button for "Left column sidebar."  Inside CC, my newsletter looks great, complete with sidebar.  However, when I send a "test," the recipient's newsletter doesn't have a sidebar, it has 2 equally-spaced columns.  Given that the sidebar information is limited and in a smaller font, the end result does not look good. 

Has anyone had this same problem and been able to remedy it? 

In advance, thank you.