What is the difference between Cloudmark content filtering and IP blocklisting?

The key difference lies in what Cloudmark is filtering. Content filtering flags your email based on its text, links, images, or attachments. IP blocklisting (CSI) is when your sending IP address has a poor reputation, often due to spam complaints or hitting spam traps . Bounce messages usually indicate which type of block occurred.

What is the best way to contact Cloudmark about content filtering?

For content filtering issues, you should use the general Cloudmark Support page to submit a ticket. Avoid using specialized internal tools unless you have direct customer access. For IP blocklisting (blacklist) issues, use the Cloudmark CSI remediation form .

What information should I include when contacting Cloudmark?

Provide full email headers, the complete content of the blocked email (preferably as an EML file), any bounce messages received, your sending IP address, and the dates and times of the incidents. A clear explanation of why the email is legitimate is also helpful.

What kind of content triggers Cloudmark filters?

Cloudmark looks for various signals, including unusual formatting, too many images compared to text, suspicious links, and keywords associated with spam. Their system is adaptive, so what triggers it can evolve. Sending to recipients who mark your email as spam also trains their filters against your content.

What steps can I take to prevent future content filtering issues?

Beyond contacting Cloudmark, revise your email content to remove any suspicious elements. Focus on a good text-to-image ratio, clear links, and authentic language. Also, maintain a healthy sender reputation by managing your mailing lists, monitoring complaint rates, and ensuring proper email authentication (SPF, DKIM, DMARC) are in place.

How do I address Cloudmark regarding content filtering issues? - Troubleshooting - Email deliverability - Knowledge base

Dealing with Cloudmark content filtering issues can be a frustrating experience. It is often different from an IP block (or blacklist) listing and requires a distinct approach. I have seen many senders struggle with where to even begin when their legitimate emails are flagged by Cloudmark's sophisticated content analysis.

Cloudmark employs a multi-layered, reputation-based system that analyzes billions of messages daily. Their filtering doesn't just look at IP addresses, it deeply inspects message content to identify spam, phishing, and other threats. This content-based filtering relies on 'fingerprints' of messages identified as malicious by their global threat network, which means even minor changes in your email's text, images, or links could trigger a filter.

This guide will walk you through the proper steps to address Cloudmark content filtering issues, from identifying the problem to submitting a remediation request and implementing long-term solutions. My aim is to help you restore your email deliverability and ensure your messages reach their intended recipients.

Identifying the type of block

Before you can address a content filtering issue, you need to confirm that Cloudmark is indeed the cause and that it is a content-related block, not an IP blocklist (or blacklist). Cloudmark uses two primary systems that often get confused: Cloudmark Sender Intelligence (CSI) for IP reputation and their content filtering system.

Content filtering issues

Focus: Analyzes email message body, headers, links, and attachments for spammy characteristics or known malicious 'fingerprints.'
Symptoms: Emails might be rejected with generic content-related bounce messages like "content not accepted," "message detected as spam," or simply disappear without an IP block bounce.
Resolution: Requires modifying email content and potentially submitting a remediation request via their support portal.

IP blocklist (CSI) issues

Focus: Monitors the reputation of sending IP addresses based on spam complaints, spam trap hits (what we call a Cloudmark trap hit), and other metrics.
Symptoms: Bounce messages explicitly stating "Cloudmark CSI" or similar IP-related block messages. Your sending IP address is blacklisted.
Resolution: Requires delisting requests via the Cloudmark CSI remediation form.

The critical first step is to analyze your bounce messages. If you receive a bounce, carefully read the error code and message. It will often indicate whether it is an IP-related blocklist (blacklist) issue or a content-related rejection. If no bounce is received and emails simply vanish, it leans more towards a content filtering problem.

You can use an email deliverability test to simulate sending to various providers, including those using Cloudmark, and receive detailed reports on where your emails land and any rejection messages.

Analyzing your email content

Once you've determined that your issue is related to content filtering, the next step is to understand what specific elements in your email might be triggering Cloudmark. Cloudmark's system is highly adaptive, learning from widespread spam patterns and user feedback. This means what worked yesterday might not work today.

Common culprits include:

Suspicious links: Links to domains with poor reputations, shortened URLs, or an excessive number of links. Make sure your domain reputation is clean.
Spammy keywords/phrases: While less common with advanced filters like Cloudmark, certain words or patterns can still trigger flags, especially when combined with other suspicious elements.
Image-to-text ratio: Emails with too many images and too little text can be a red flag, as spammers often use images to bypass text-based filters.
Attachments: Certain file types or suspicious content within attachments can lead to blocking.
Formatting issues: Poor HTML, broken links, or obfuscated content.

Content test messages

One effective strategy is to send incremental content test messages. Start with a plain text email. If it goes through, gradually add elements back into your message (HTML, images, links) until you identify the specific element or combination that triggers the filter. This process helps pinpoint the problematic content quickly.

Contacting Cloudmark support

Unlike IP blocklist (blacklist) issues that might have a dedicated portal like CSI, content filtering issues generally require direct engagement with Cloudmark's support team. It is essential to have all the necessary information ready when you reach out.

Gathering information

Before contacting support, compile the following:

Full email headers: These contain crucial routing information and can help Cloudmark trace the email.
Complete bounce messages: If available, include the full text of any non-delivery reports (NDRs).
Content of the blocked email: Provide the exact email (preferably as an EML file) that was blocked.
Sending IP address: The IP address your email originated from.
Specific dates and times: When the incidents occurred.
Clear explanation: Describe the issue and why you believe the email is legitimate.

Submitting a request

The recommended channel for content filtering issues is through their general support portal. Avoid using any specific internal tools like "CAT" unless you are a direct customer with access, as these are not for public use.

You can typically submit a ticket via the Cloudmark Support page. Be patient, as responses can take some time. Follow up politely if you don't hear back within their stated timeframe.

For more detailed guidance on what data to include, you can refer to our guide on how to submit Cloudmark remediation requests using email fingerprint data and headers. This can significantly speed up the investigation process.

Proactive content and sending hygiene

While awaiting a response from Cloudmark, and to prevent future issues, it's crucial to adopt best practices for email content and overall sending hygiene. A proactive approach is always more effective than reactive troubleshooting.

Content best practices

Clear and concise subject lines: Avoid misleading or overly promotional language.
Maintain a healthy text-to-image ratio: Ensure your email isn't just one large image.
Reputable links: Use full, recognizable URLs and avoid excessive redirects or link shorteners.
Personalization: Personalize emails where appropriate to increase engagement and reduce spam complaints.

Overall deliverability

Remember that content is just one piece of the deliverability puzzle. Your overall sender reputation, bounce rates, complaint rates, and authentication (SPF, DKIM, DMARC) also play significant roles. A poor sender reputation can amplify the impact of even minor content issues, leading to your emails getting blocked or landing in the spam folder.

For a comprehensive understanding of why your emails might be going to spam and how to address those issues, consider reviewing our guide on why your emails are going to spam. Maintaining a healthy email ecosystem is a continuous effort.

Views from the trenches

Best practices

Actively monitor your email bounce messages for specific Cloudmark content filtering errors.

Segment your audience and tailor content to minimize irrelevant sending and reduce spam complaints.

Use a clear call to action and avoid manipulative language or overly aggressive sales tactics.

Ensure your email authentication (SPF, DKIM, DMARC) is correctly configured and aligned.

Common pitfalls

Confusing content filtering issues with IP blocklists and using the wrong remediation form.

Not providing full email headers and bounce messages when contacting Cloudmark support.

Making significant content changes without testing, potentially triggering new filters.

Neglecting overall sender reputation and list hygiene while focusing solely on content.

Expert tips

When testing, send messages with minimal content first, then gradually add elements to isolate the problem.

Keep records of all communication with Cloudmark support, including dates and reference numbers.

Review Cloudmark's documentation and whitepapers for insights into their filtering mechanisms.

Regularly check your domain and IP on common blocklists to catch issues early.

Expert view

Expert from Email Geeks says that CAT (Cloudmark Analytics Tool) is primarily for Cloudmark customers and not for general use or for re-using data from other sources. Content issues should be addressed through the standard support channels.

2023-11-09 - Email Geeks

Marketer view

Marketer from Email Geeks says that for content filtering, the process involves submitting tickets via the Cloudmark support page, which has been consistent for many years.

2023-11-09 - Email Geeks

Final thoughts on Cloudmark content filtering

Addressing Cloudmark content filtering issues requires a clear understanding of their system, meticulous content analysis, and a structured approach to remediation. It is distinct from managing IP blocklist (blacklist) removals, though both impact deliverability.

By carefully reviewing bounce messages, analyzing your email content for potential triggers, and submitting detailed, informed requests through the correct Cloudmark support channels, you can increase your chances of resolving these issues. Simultaneously, adopting ongoing best practices for content and sender reputation will help prevent future filtering problems.

Remember, good email deliverability is built on trust and consistent adherence to best practices, ensuring your messages are welcomed in the inbox.