View Standard Fix
ERROR TYPE Target

Outlook Email Broken Layout Fix: Resolve CSS Flexbox Collapse for Deliverability & Spam Audits

Spam filters analyze email HTML code quality alongside body copy. Unclosed tags, excessive styling block nesting, and broken link parameters are flagged as spam risks. Below is the targeted integration guide to fix CSS Flexbox Collapse inside Outlook Office 365 (Web) templates when using SendGrid.

Technical Breakdown

Outlook Office 365 (Web) uses the Office Rendering Service which lacks support for standard rendering rules. This causes CSS Flexbox Collapse elements to break or collapse when rendering templates.

SendGrid Behaviors

SendGrid's template parser automatically injects custom style tags that can override inline styles. Always use inline style definitions and define clear target widths. Run your finished layouts through the Spam Word Auditor to catch trigger phrases and verify structural delivery alignments before launching.

Remediation Code Block

To resolve this, modern layouts must be compiled down to Outlook-compliant nested HTML table models. Each flex container becomes a table row, and each flex child becomes a table data cell (td) with explicit pixel or percentage widths. In your SendGrid campaign manager, make sure you configure your links to run via {{{unsubscribe}}}.

<table role="presentation" border="0" cellpadding="0" cellspacing="0" width="100%">
  <tr>
    <td width="50%" valign="top" style="padding: 20px;">Column 1</td>
    <td width="50%" valign="top" style="padding: 20px;">Column 2</td>
  </tr>
</table>

Live Code Sandbox Test

Interactive SendGrid Custom Sandbox

Target Environment: Outlook Office 365 (Web)

How to Deploy inside SendGrid

1

Copy the fixed VML or table wrapper code block from the remediation box above.

2

Open SendGrid Design Editor, toggle the view mode to Code Editor, or insert a custom 'Code' module block inside your drag-and-drop layout. Drop the corrected code inside the box.

Targeted Fixes by Use Case & Industry