What does Apple's 'Message rejected due to local policy' error mean, and how can it be resolved?
Matthew Whittaker
Co-founder & CTO, Suped
Published 30 Apr 2025
Updated 19 Aug 2025
6 min read
Receiving an email bounce message that states "550 5.7.1 [CS01] Message rejected due to local policy" from an Apple Mail or iCloud address can be frustrating. This error indicates that Apple's mail servers have rejected your message based on their internal filtering rules and policies. It's a common deliverability hurdle for senders, especially those sending bulk or marketing emails.
The phrase "local policy" refers to the recipient mail server's (in this case, Apple's) specific rules and criteria for accepting or rejecting incoming mail. These rules are designed to protect their users from spam, phishing, and other unwanted communications. When your email triggers one of these policies, it's blocked, and you receive this bounce.
Understanding this error is the first step toward resolving it. This guide will help you understand the common causes behind Apple's local policy rejections and provide actionable steps to get your emails successfully delivered to Apple recipients.
The "CS01" code often points to Proofpoint (which acquired Cloudmark) as the underlying filtering service Apple uses for its email systems. This means the rejection isn't necessarily a direct blacklist by Apple itself, but rather a determination made by Proofpoint's sophisticated spam and abuse detection systems.
Proofpoint's filters evaluate numerous factors to determine an email's legitimacy, including sender reputation, authentication, and content. If any of these factors raise a red flag, the message is likely to be rejected under a local policy. This comprehensive evaluation is why identifying the exact cause can be challenging.
Understanding that Proofpoint is involved helps to narrow down the potential reasons for the rejection. For more details on this specific error, you can read our article What causes Apple's policy-related (CS01) bounce messages.
Common triggers for local policy blocks
Several factors can trigger Apple's local policy (or blacklist) rejections. These generally fall into categories related to your sending practices and email configuration. Addressing these areas is crucial for improving your email deliverability to Apple users.
Sender reputation: A poor sender reputation due to high spam complaint rates, low engagement, or sending to invalid addresses can quickly lead to blocks. Recovering domain reputation can be a lengthy process.
Email authentication: Insufficient or misconfigured SPF, DKIM, and DMARC records are common reasons for email rejection. Strong authentication proves your emails are legitimate and not spoofed.
Content issues: Certain content elements, such as suspicious links (especially those from shared URL shorteners with poor reputations), unusual formatting, or spammy keywords, can trigger content-based filters.
IP or domain blocklists: If your sending IP or domain is listed on a major blocklist (or blacklist), Apple's filters, which often consult these lists, will likely reject your mail.
The involvement of Cloudmark (Proofpoint) highlights the importance of adhering to industry best practices, as their filtering systems are constantly updated to combat evolving spam tactics. For more information, please see our article Why are my emails blocked by Apple Mail and Proofpoint.
Steps to resolve the issue
Resolving Apple's "message rejected due to local policy" error requires a systematic approach. Start by diagnosing the potential causes and then implement corrective measures. This process often involves checking your existing email setup and making adjustments to your sending behavior.
Check blocklists (blacklists): Use a blocklist checker to see if your sending IP or domain is listed. Even minor listings can impact deliverability to sensitive inboxes like Apple's.
Review email content: Look for anything that might be flagged as spam, such as excessive links, suspicious keywords, or common spam triggers.
Resolution
Correct authentication issues: Update your DNS records for SPF, DKIM, and DMARC. Ensure DMARC is set to a policy like `p=quarantine` or `p=reject` for optimal protection.
Improve sender reputation: Focus on sending only to engaged subscribers. Implement list cleaning practices to remove inactive or invalid addresses, reducing bounce rates and spam trap hits.
Adjust email content: Rewrite subject lines and body copy to be less spammy. Avoid generic or low-reputation URL shorteners and consider using your own branded links.
Request delisting: If your IP or domain is on a public blacklist, follow the delisting procedures of that specific blocklist. If it's a private blocklist (e.g., Proofpoint's internal list), focus on improving overall sending practices.
In some cases, especially if you believe the block is unjustified after reviewing your practices, directly contacting Apple's iCloud Postmaster can be beneficial. Provide them with relevant details, such as the bounce message and any steps you've already taken to resolve the issue.
Long-term deliverability strategies
Preventing future "message rejected due to local policy" errors from Apple requires ongoing attention to your email program's health. It's not a one-time fix but a continuous effort to maintain a good sender reputation and adhere to best practices. This proactive approach ensures consistent inbox placement for your emails.
One key aspect is maintaining excellent list hygiene. Regularly removing invalid, inactive, or unengaged subscribers from your mailing list helps reduce bounce rates and avoid spam traps, both of which negatively impact your sender reputation and can lead to local policy blocklists.
Another crucial strategy is robust email authentication. Moving your DMARC policy to enforcement (p=quarantine or p=reject) is a strong signal to mailbox providers like Google and Yahoo that your emails are legitimate. This helps build trust and reduces the likelihood of being flagged by local policy filters. Continuous DMARC monitoring provides valuable insights into authentication failures.
Finally, regular blocklist (or blacklist) monitoring is essential. Being proactive about removing your IP or domain from any blocklists will significantly improve your chances of reaching the inbox. This comprehensive approach to email deliverability ensures that your messages are consistently seen as trustworthy by providers like Apple.
Views from the trenches
Best practices
Maintain high engagement rates by sending relevant content to interested subscribers.
Implement a double opt-in process for all new subscribers to ensure consent and reduce spam complaints.
Regularly clean your email list to remove inactive subscribers and hard bounces.
Ensure all email authentication protocols (SPF, DKIM, DMARC) are correctly configured.
Common pitfalls
Ignoring bounce messages and continuing to send to problematic addresses.
Using generic or shared URL shorteners that have a poor reputation.
Not monitoring your sender reputation or blocklist status regularly.
Sending emails with content that closely resembles known spam patterns.
Expert tips
If the issue persists, consider segmenting your audience and sending smaller batches.
Always include a clear and easy-to-use unsubscribe link in all your marketing emails.
Test your email content and sending setup before sending large campaigns to Apple recipients.
Monitor your DMARC reports for insights into authentication failures affecting Apple.
Expert view
Expert from Email Geeks says that Apple generally lacks real-time insight into individual complaints, and the CS code often points to Cloudmark, which is now part of Proofpoint.
2020-02-05 - Email Geeks
Marketer view
Marketer from Email Geeks says that they resolved this issue for a client sending marketing emails by contacting the iCloud postmaster address.
2020-02-05 - Email Geeks
Ensuring successful email delivery to Apple
The "Message rejected due to local policy" error from Apple (and iCloud) is a clear signal that your email sending practices need review. It highlights the stringent filtering mechanisms that major mailbox providers employ to protect their users. While initially daunting, this bounce message provides an opportunity to enhance your overall email deliverability strategy.
By diligently addressing sender reputation, ensuring proper email authentication (SPF, DKIM, DMARC), carefully reviewing content, and actively monitoring blocklists (blacklists), you can significantly reduce the occurrence of these rejections. Proactive maintenance and adherence to email best practices are key to ensuring your messages consistently reach their intended Apple recipients.
Remember that deliverability is an ongoing process. Regularly analyzing your email performance data and adapting your sending methods will not only resolve this specific error but also build a stronger, more reliable email program for long-term success.
Proofpoint (which acquired Cloudmark) as the underlying filtering service Apple uses for its email systems. This means the rejection isn't necessarily a direct blacklist by Apple itself, but rather a determination made by Proofpoint's sophisticated spam and abuse detection systems.
Google and 
Yahoo that your emails are legitimate. This helps build trust and reduces the likelihood of being flagged by local policy filters. Continuous DMARC monitoring provides valuable insights into authentication failures.
