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 App (iOS & Android) templates when using Brevo (Sendinblue).
Technical Breakdown
Outlook App (iOS & Android) uses the WebKit / Blink Wrapper which lacks support for standard rendering rules. This causes CSS Flexbox Collapse elements to break or collapse when rendering templates.
Brevo (Sendinblue) Behaviors
Brevo's rendering system injects inline spacing helpers to support their responsive editor, which can cause column overlaps in Outlook. Using explicit table alignments is required. 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 Brevo (Sendinblue) 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
How to Deploy inside Brevo (Sendinblue)
Copy the fixed VML or table wrapper code block from the remediation box above.
Open Brevo's template canvas, select the element you wish to configure, click 'Edit HTML' or insert a standalone 'HTML' content block, and paste the code.