How to troubleshoot blank email content issues in Pardot/MCAE?
Michael Ko
Co-founder & CEO, Suped
Published 20 Jun 2025
Updated 18 Aug 2025
6 min read
Dealing with blank email content in Pardot (now Marketing Cloud Account Engagement or MCAE) can be incredibly frustrating. Imagine sending a crucial campaign, only to find that some recipients receive a subject line but no body content, while others, even within the same company, see the email perfectly. This perplexing issue often leaves marketers scratching their heads, wondering if it's a security filter, a rendering bug, or something else entirely.
When you encounter this, your first thought might be an aggressive email security system, and that's a valid suspicion. However, the root cause can often be more nuanced, involving specific HTML/CSS quirks or the way email clients interpret your code. I've encountered this scenario many times, and a systematic approach is key to diagnosing and resolving it.
Common causes of blank emails
One of the most frequent culprits behind blank email content, especially when it's inconsistent across recipients or email clients, is problematic HTML and CSS. Email clients, particularly older versions of Outlook or Microsoft 365, do not render HTML and CSS uniformly. They often use their own rendering engines, which can be less forgiving than web browsers.
Specific issues often arise from nested conditional comments (e.g., <!--[if mso]>). While these are designed to target specific Microsoft clients, improper nesting or complex logic within them can cause entire sections of your email to disappear. Other common culprits include missing closing tags, unsupported CSS properties, or malformed HTML structures that lead the rendering engine to simply give up.
Always ensure your emails include a well-formatted plain text version as a fallback. If the HTML fails to render for any reason, the email client can display the plain text content instead of a blank screen. This is a best practice for email deliverability and accessibility.
To preemptively catch these issues, thorough testing across various email clients is non-negotiable. Tools exist specifically for this purpose, providing screenshots of your email's appearance in different environments. This helps you diagnose email rendering variances before your campaign ever hits an inbox.
Typical HTML/CSS errors
Conditional comments (MSO): Improperly nested or overly complex <!--[if mso]> statements can break rendering, especially in Outlook. Ensure these are clean and simple.
Unsupported CSS: Modern CSS properties may not be supported by all email clients. Stick to inline or embedded CSS and avoid shorthand properties where possible.
Malformed HTML: Missing closing tags, incorrect tag nesting, or broken table structures can cause the email to display incorrectly or not at all.
Image issues: If emails are heavily image-based and images fail to load (e.g., due to firewall, broken URLs), the email may appear blank.
Advanced troubleshooting with email headers and security
When a simple rendering issue isn't the cause, the problem often points to email security systems. Enterprise email filters can be quite aggressive, sometimes stripping out parts or even all of an email's content if they detect anything suspicious. This can range from malicious code to unusual formatting, or even content that triggers their spam rules.
The most effective way to investigate this is by examining the raw email message. This involves getting the original email file from a recipient who received a blank email (if possible) or comparing the headers of a working email to a blank one. Look for Content-Type headers, Content-Transfer-Encoding, and any unusual headers added by security gateways, like X-Spam-Status or X-Forefront-Antispam-Report. These can provide clues about what happened to the content.
It's also worth checking if your sending domain or IP has landed on any email blacklist (or blocklist). While being blocklisted usually results in outright rejection or spam folder delivery, some highly sensitive filters might strip content. However, this is less common for content stripping alone.
Ensure your email authentication records (SPF, DKIM, DMARC) are correctly configured. While these primarily impact deliverability to the inbox versus spam, misconfigurations can sometimes lead to emails being treated with suspicion, potentially triggering content-stripping filters. For instance, you can troubleshoot SPF validation errors that could impact your sender reputation and content integrity.
Content rendering problems
Email client compatibility: Variations in how email clients, especially desktop versions of Outlook, render HTML and CSS. This often leads to elements being ignored or breaking the layout.
HTML validation errors: Syntax errors, unclosed tags, or improper nesting can cause an email client to simply stop rendering content beyond the error point.
Image display issues: If email content is primarily images and they fail to load due to incorrect paths, server issues, or recipient security settings, the email appears blank.
Security filtering and content stripping
Content stripping by filters: Advanced security solutions (firewalls, email gateways) at the recipient's domain can modify or remove email content if it triggers their specific rules for spam, phishing, or malware.
Reputation-based filtering: A low sender reputation or an IP/domain on a blocklist might cause mail servers to handle your emails more aggressively, sometimes resulting in content suppression.
Email authentication failures: While less direct, issues with SPF, DKIM, or DMARC can contribute to emails being flagged, leading to more stringent content filtering or even complete rejection.
Practical steps and prevention
The most definitive way to understand what's happening is to get the full, raw email message from an affected recipient. This is the email as it was actually received, before any client-side rendering. Recipients can often provide this by using an option like "Show original" or "Download original message" in their email client, which typically saves it as an .eml file.
Once you have the raw message, you can open it in a text editor. You'll likely see parts of the email encoded in Base64, especially the HTML and plain text bodies. You'll need to decode these sections to view the actual content that was received. There are many online Base64 decoding tools or command-line utilities that can help with this. Compare the decoded content to what you expected to send.
For ongoing prevention, leverage email testing platforms (like Litmus or Email on Acid) that offer comprehensive previews across a wide range of email clients and devices. These services can flag potential rendering issues before you hit send. Also, utilize Pardot's own email testing guide to ensure your content is clean.
Finally, if you're experiencing inconsistent issues like this, it's helpful to review your overall email deliverability strategy. Understanding why your emails are going to spam can shed light on underlying issues that might indirectly contribute to content stripping by stricter security systems.
Example of a raw email snippet with Base64 encoding
Troubleshooting blank email content issues in Pardot/MCAE can be complex, often requiring a deep dive into your email's underlying HTML and its interaction with various email clients. While aggressive email security systems can strip content, more often, it's a specific rendering quirk or a slight HTML/CSS misconfiguration that causes the problem.
By understanding common pitfalls, utilizing email testing tools, and knowing how to inspect raw email messages (including decoding Base64 content), you can effectively diagnose and resolve these perplexing deliverability challenges. A proactive approach to email coding and consistent testing will significantly reduce instances of blank emails and ensure your messages always reach their recipients as intended.
Views from the trenches
Best practices
Always include a robust plain text version of your email to serve as a fallback if the HTML fails to render, ensuring content is always visible.
Test emails across a wide array of email clients and devices using dedicated testing platforms to identify rendering inconsistencies proactively.
Adhere strictly to email-safe HTML and CSS practices, prioritizing simplicity and broad compatibility over cutting-edge web design techniques.
Common pitfalls
Using overly complex or improperly nested MSO conditional comments, which can lead to email content being stripped or ignored by Outlook.
Relying heavily on images without providing adequate alt text or a plain text alternative, making emails appear blank if images fail to load.
Ignoring email client rendering differences, leading to emails that look great in a browser but break in common email applications.
Expert tips
When troubleshooting blank emails, prioritize obtaining the raw message from an affected recipient; it provides the most accurate view of what was received.
Master Base64 decoding for email content. It's an indispensable skill for deeply analyzing what email security systems or clients might be receiving.
If the email is a clone of a previous successful send, focus on any changes, however minor, between the two versions, as they often contain the culprit.
Expert view
Expert from Email Geeks says that enterprise email filters are unlikely to defang mail without leaving detritus about why, or quarantining it. It's more likely a weird message corruption or rendering issue, potentially caused by interaction between an odd mail structure and a spam filter.
2024-01-21 - Email Geeks
Marketer view
Marketer from Email Geeks says that testing with Litmus revealed the problem was bad nested MSO CSS statements, which older versions of Outlook and Office 365 did not render correctly, leading to blank content.
Outlook or 
Microsoft 365, do not render HTML and CSS uniformly. They often use their own rendering engines, which can be less forgiving than web browsers.
