Summary
Emails to Apple domains (icloud.com, me.com, and mac.com) bounce due to a confluence of factors. Apple's infrastructure, including temporary outages, aggressive spam filtering, and storage limitations, can cause bounces. Sender-side issues also play a significant role, including poor sender reputation, incorrect email authentication (SPF, DKIM, DMARC), being blocklisted, sending to invalid addresses, and greylisting. Successful deliverability requires diligent management of sender reputation, proper email authentication setup, and proactive monitoring of blocklists and system status updates. Temporary faults are generally resolved quickly, but still, need to be handled and can add to the list cleaning process. Recipient-side full mailboxes are also a potential cause.
Key findings
- Infrastructure Issues: Apple's iCloud outages can cause widespread bounce issues which are typically resolved by Apple.
- Aggressive Spam Filtering: Apple is known for its aggressive spam filters, potentially blocking legitimate emails.
- Authentication Failures: Failing SPF, DKIM, and DMARC checks is a major contributor to email bounces.
- Blocklisting: Being listed on a blocklist significantly increases the likelihood of bounces to Apple domains.
- Full Mailboxes: When a recipient's iCloud storage is full, emails will bounce back to the sender.
- Invalid Addresses: Sending to invalid or non-existent email addresses results in bounces.
- Poor Sender Reputation: A poor sender reputation increases the probability of emails being rejected.
- Greylisting: Apple may implement greylisting, causing temporary rejections from unknown senders.
- Temporary Faults: Temporary faults within the Apple infrastructure can lead to bounce issues which can be quickly resolved
Key considerations
- Monitor System Status: Regularly check Apple's system status page for any reported outages.
- Implement Authentication: Ensure proper setup of SPF, DKIM, and DMARC records.
- Clean Email Lists: Routinely clean email lists by removing invalid or inactive addresses.
- Manage Sender Reputation: Actively work on improving sender reputation by reducing spam complaints and bounce rates.
- Monitor Blocklists: Regularly check your sending IP and domain on blocklists.
- Manage iCloud Storage: Recipients should manage their iCloud storage to ensure they can receive emails.
- Retry sending: Temporary Faults can resolve themselves and the email can then be re-sent
What email marketers say
13 marketer opinions
Emails to Apple domains (icloud.com, me.com, mac.com) can bounce due to a variety of reasons ranging from temporary Apple server outages and stricter spam filtering to sender reputation issues, incorrect email authentication (SPF, DKIM, DMARC), full user mailboxes, invalid email addresses, and blocklisting. Temporary issues are often resolved quickly, while others require sender-side action.
Key opinions
- Apple Outages: Temporary iCloud outages can cause widespread bounces. Check Apple's system status page.
- Strict Spam Filters: Apple's spam filters are known to be more aggressive, potentially misclassifying legitimate emails.
- Sender Reputation: Poor sender reputation (due to spam complaints, bounce rates, etc.) can lead to bounces.
- Authentication Issues: Incorrect or missing SPF, DKIM, and DMARC records can cause Apple's servers to reject emails.
- Full Mailboxes: Recipients exceeding their iCloud storage limits will cause bounces.
- Invalid Addresses: Bounces can occur if the email address is invalid or no longer exists.
- Blocklisting: If your IP or domain is on a blocklist, emails to Apple domains will bounce.
- Greylisting: Apple uses greylisting, temporarily rejecting emails from unknown senders, to verify legitimacy.
Key considerations
- Monitor System Status: Check Apple's system status page for reported outages before troubleshooting further.
- Improve Sender Reputation: Reduce spam complaints, manage bounce rates, and improve overall engagement.
- Implement Email Authentication: Ensure SPF, DKIM, and DMARC records are correctly configured.
- Clean Email Lists: Regularly remove invalid or inactive email addresses from your lists.
- Address Blocklisting: If blocklisted, take steps to get removed from relevant blocklists.
- Retry Sending: For temporary server issues or greylisting, resending the email later may be successful.
Marketer view
Email marketer from Email Marketing Forum explains that Apple may implement greylisting, a technique where the server temporarily rejects an email from an unknown sender. This is to verify the email is legitimate, after a delay it is accepted.
17 May 2024 - Email Marketing Forum
Marketer view
Marketer from Email Geeks reports that Apple is indicating the issue is resolved, and they are seeing successful deliveries again.
16 Nov 2023 - Email Geeks
What the experts say
3 expert opinions
Emails to Apple domains (icloud.com, me.com, and mac.com) bounce for several reasons. One cause is related to authentication failures (SPF, DKIM, DMARC). Apple's aggressive spam filters and robust security measures can also contribute to bounces, even when best practices are followed. Some bounces may be temporary with messages being delivered eventually, but can still be recorded as hard bounces and added to suppression lists. Excellent list hygiene and strong audience engagement are key to deliverability.
Key opinions
- Authentication Failures: Failing SPF, DKIM, and DMARC checks is a primary reason for bounces to Apple domains.
- Aggressive Spam Filters: Apple employs strong spam filters that can cause bounces even when senders follow best practices.
- Hard Bounces and Suppression: Temporary bounces can be recorded as hard bounces, leading to additions to suppression lists.
Key considerations
- Implement Authentication: Ensure correct setup of SPF, DKIM, and DMARC to prevent authentication-related bounces.
- Maintain List Hygiene: Practice excellent list hygiene to minimize bounces and improve deliverability.
- Enhance Audience Engagement: Focus on audience engagement to improve sender reputation and avoid spam filters.
- Manage Suppression Lists: Regularly review and manage suppression lists to ensure valid contacts are not inadvertently blocked.
Expert view
Expert from Email Geeks refers to a MacRumors forum thread indicating that messages will eventually be delivered. He notes that the bounces were recorded as hard bounces and added to his suppression file.
4 Feb 2024 - Email Geeks
Expert view
Expert from Word to the Wise explains that Apple domains are known for having aggressive spam filters and robust security measures which can be a reason for bounces even if best practices are followed. They highlight that focusing on audience engagement and excellent list hygiene will help with deliverability.
15 Jun 2024 - Word to the Wise
What the documentation says
5 technical articles
Emails to Apple domains (icloud.com, me.com, and mac.com) can bounce due to recipients exceeding their iCloud storage limits. Additionally, being listed on the Spamhaus blocklist can lead to rejections. Authentication failures, specifically DKIM and DMARC, are also significant causes. The 5xx SMTP error codes indicate permanent delivery failures, with various underlying reasons.
Key findings
- Storage Limits: Recipients exceeding their iCloud storage quotas will cause emails to bounce back to the sender.
- Blocklisting: Being listed on the Spamhaus blocklist can result in emails being rejected by Apple's servers.
- Authentication Failures: DKIM and DMARC authentication failures are a primary cause for bounces due to Apple's security measures.
- SMTP 5xx Errors: 5xx SMTP error codes signal permanent failures that can result from problems with the sending or receiving server.
Key considerations
- Monitor Blocklists: Regularly check your sending IP and domain against blocklists like Spamhaus and take remediation steps if listed.
- Implement Authentication: Ensure that DKIM and DMARC are correctly configured to avoid authentication failures and improve deliverability.
- Handle Bounces: Properly handle 5xx SMTP errors by removing bounced addresses from mailing lists to avoid future deliverability issues.
- Inform Recipients: Advise recipients to manage their iCloud storage to prevent full mailboxes.
Technical article
Documentation from Apple Support explains that one reason for bounces to iCloud, me.com, and mac.com addresses could be the recipient exceeding their iCloud storage limits. When the storage is full, incoming emails will bounce back to the sender.
4 Jul 2021 - Apple Support
Technical article
Documentation from Spamhaus explains that being listed on the Spamhaus blocklist can cause email delivery issues to various domains, including Apple's. If a sending server's IP address is listed, emails may be rejected.
19 Jul 2022 - Spamhaus
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