Not all email programs respect the HTML and CSS in an email message, even though the HTML and CSS are perfectly valid per W3C standards.

The WYSIWYG Editor cannot be used to create borders for Outlook as Outlook does not recognize the HTML border-color CSS that is generated by the Editor.  However the CSS shorthand can be manually substituted instead. This would be written as follows:
  1. Navigate to Communications > eMail
  2. Hover over your Campaign and click Manager
  3. Click the content for your mailing
  4. Click HTML in the bottom lefthand corner of the Editor to switch to HTML View
  5. Locate your image and adjust the style tag with the following tag
    • style="border: 1px solid #abc123"  
  6. Click Save

Refer to the following Knowledgebase article for other troubleshooting steps specific to Outlook Formatting Issues.