Issue

Emails built with the Sender.net drag-and-drop editor produce horizontal line rendering artifacts in Microsoft Outlook (Windows). This is a known Outlook issue caused by its Word-based rendering engine, which handles table cell spacing differently from standard browsers.

Root Cause

The generated email code does not include the standard Outlook fix (there may be more fixes):

<!--[if mso]>

<style type="text/css">

table { border-collapse: collapse !important; }

td { mso-table-lspace: 0pt; mso-table-rspace: 0pt; }

img { display: block !important; }

</style>

<![endif]-->

This Conditional Comment is ignored by all other email clients and only read by Outlook — making it a safe, non-disruptive fix.

Workaround Attempted

We tried adding the fix manually via the Custom HTML block in the drag-and-drop editor. The block actively strips <style> tags and Conditional Comments, making a user-side fix impossible.

Requested Fix — either of the following: