By default AOL uses it’s own font styling. The fix is very simple and can be overwritten using your own embedded CSS.
AOL Mail HTML codes
You can target AOL Mail by including the CSS class .aolReplacedBody and adding your styles.
Some email clients and webmail services such as AOL Mail, Gmail, Lotus, Outlook, Thunderbird, and Windows Mail will display a blue or black border around images that are linked but don’t have a border specified.