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ERROR TYPE Target

Fix Max-Width Constraint Collapsing in iOS Mail (Apple) — MJML Framework 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 iOS Mail (Apple) templates when using MJML Framework.

Technical Breakdown

iOS Mail (Apple) uses the WebKit Mobile which lacks support for standard rendering rules. This causes Max-Width Constraint Collapsing elements to break or collapse when rendering templates.

MJML Framework Behaviors

The MJML transpilation compiler parses dynamic columns and wraps them in custom HTML conditional tags. If you paste direct tables or VML code blocks inside an MJML layout without proper escaping, the MJML compiler will try to clean the code, resulting in stripped Outlook namespaces and broken layouts. 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 MJML Framework campaign manager, make sure you configure your links to run via {{unsubscribe_link}}.

<!--[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

Interactive MJML Framework Custom Sandbox

Target Environment: iOS Mail (Apple)

How to Deploy inside MJML Framework

1

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

2

Wrap the entire RenderOps corrected table block inside an '<mj-raw>' tag block. This tells the MJML compiler to bypass parsing on this segment, exporting the exact conditional statements into the final HTML output.

Targeted Fixes by Use Case & Industry