Fix Max-Width Constraint Collapsing in Apple Mail (Desktop) — SendGrid Guide 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 Max-Width Constraint Collapsing inside Apple Mail (Desktop) templates when using SendGrid.
Technical Breakdown
Apple Mail (Desktop) uses the WebKit which lacks support for standard rendering rules. This causes Max-Width Constraint Collapsing 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 secure design widths, always wrap your layout inside a parent table with a static, hardcoded HTML width attribute (e.g. width='600') targeting Microsoft clients using conditional comments. In your SendGrid campaign manager, make sure you configure your links to run via {{{unsubscribe}}}.
<!--[if mso]>
<table role="presentation" align="center" border="0" cellpadding="0" cellspacing="0" width="600">
<tr>
<td>
<![endif]-->
<div style="max-width: 600px; margin: 0 auto;">
Centered Layout Content
</div>
<!--[if mso]>
</td>
</tr>
</table>
<![endif]-->Live Code Sandbox Test
How to Deploy inside SendGrid
Copy the fixed VML or table wrapper code block from the remediation box above.
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.