Why are password reset emails being blocked by Optimum/Altice, and how can it be fixed?

Key findings

• Targeted blocking: Optimum/Altice might specifically block password reset emails even if other email types from the same sender are successfully delivered. This suggests a content or policy-based filter specific to transactional or sensitive messages.
• ISP opacity: Optimum and Altice are often perceived as less responsive to deliverability issues, making direct communication or escalation challenging for senders facing blocks.
• Authentication impact: Even with correct DMARC, SPF, and DKIM authentication in place, issues like mismatched rDNS or unusual SMTP configurations can lead to blocks.
• Cloudmark non-involvement: In some cases, investigations reveal that the blocks are not related to major spam filtering services like Cloudmark, pointing towards internal ISP policies or recipient-side filtering.
• Recipient-side policies: If emails are successfully delivered but land in spam folders, the issue might be due to user-specific or default mailbox settings on the recipient's end.

Key considerations

• Isolate the sending infrastructure: Determine if password reset emails are sent from a different subdomain or IP address than marketing emails. This segregation can sometimes lead to different deliverability outcomes due to distinct reputation profiles.
• Verify authentication and configuration: Thoroughly check all technical email configurations, including SPF, DKIM, DMARC, rDNS, and SMTP settings for any anomalies.
• Content review: Examine the content of your password reset emails for any elements that could be triggering spam filters, even if they seem benign. Optimum's customer privacy policy might offer clues to their filtering logic.
• Direct engagement: Although challenging, attempts to contact Optimum/Altice postmaster or support may be necessary for specific unblock requests.

Key opinions

• ISP indifference: Many marketers express frustration over what they perceive as a lack of concern from Optimum/Altice regarding the blocking of legitimate, critical emails like password resets.
• Transactional vs. marketing: A common observation is that transactional emails, even from well-reputed senders, can face different filtering rules than marketing emails, leading to specific blocking issues.
• Content and setup: Marketers often meticulously check their infrastructure and email authentication, only to find the problem persists, suggesting a deeper filtering logic at play.
• Recipient-side filters: The possibility of recipient-specific policies or even simple user actions marking emails as spam (even unintentionally) is a known factor contributing to deliverability challenges.

Key considerations

• System separation: Assess whether different systems are used for password resets versus other emails, as this can affect reputation and filtering. If you're experiencing general email deliverability issues, consider a holistic review.
• Content specificity: Review the specific content, links, and formatting of password reset emails. Even subtle elements can trigger filters, especially with sensitive content. For tips on managing password reset emails, consumer advice can be helpful.
• Logging and diagnostics: Ensure comprehensive logging is in place to confirm successful delivery attempts, even if emails aren't reaching the inbox. This helps differentiate between hard blocks and spam folder placement.
• Recipient education: Consider advising users to check their spam folders or add your sending domain to their safe sender list for critical emails like password resets. Learning why emails fail is key.

Key opinions

• Persistent challenges: Experts often cite Optimum/Altice as particularly difficult to work with on deliverability issues, noting a long-standing history of being less proactive in resolving blocks.
• Technical root causes: Beyond content, technical misconfigurations such as incorrect rDNS records, unusual SMTP setups, or authentication errors (SPF, DKIM, DMARC) are frequently pinpointed as culprits.
• Specific filtering: Different email streams (e.g., transactional vs. marketing) are often treated differently by ISPs, even from the same sender, due to varying risk profiles or content sensitivity.
• Beyond blacklists: In many cases, blocks are not due to public blacklists or blocklists like Cloudmark, but rather internal, proprietary filtering rules or recipient-level settings.

Key considerations

• Deep technical audit: Conduct a thorough review of all aspects of your sending infrastructure, including DMARC, SPF, and DKIM alignment, rDNS, and any non-standard SMTP settings.
• Content variations: Experiment with minimal content in password reset emails to identify if specific keywords, URLs, or formatting are triggering filters.
• Engagement patterns: While password resets are essential, monitor overall engagement with your transactional emails. Low engagement can indirectly affect reputation over time.
• Direct communication (if possible): Even if challenging, gathering specific bounce codes or engaging with any available ISP postmaster contacts can provide crucial debugging information. Spamresource.com offers insights into understanding ISP relations.

Key findings

• Standard compliance: RFCs (Requests for Comments) define the technical standards for email protocols, including SMTP, which governs how mail servers communicate.
• Authentication importance: Standards for SPF, DKIM, and DMARC emphasize sender authentication as crucial for combating phishing and spoofing, which ISPs rigorously check.
• Reputation signals: Documentation often implies that a sender's historical behavior and adherence to best practices directly influence their reputation with mailbox providers.
• Content analysis: While not always explicit, industry guidelines suggest that sensitive transactional emails (like password resets) are subject to heightened content scrutiny to prevent abuse.

Key considerations

• Adherence to RFCs: Ensure your sending infrastructure strictly adheres to relevant RFCs, such as RFC 5321 for SMTP, to ensure proper technical handshake with recipient servers. Our article on what RFC 5322 says versus what works can be a useful read.
• Consistent authentication: Maintain robust and correctly configured SPF, DKIM, and DMARC records across all sending IPs and domains, particularly for transactional streams. Even small errors, like an SPF DNS timeout, can cause issues.
• Monitor deliverability metrics: Regularly review your deliverability metrics and any bounce messages from Optimum/Altice. While explicit policies are scarce, their privacy policy offers general statements on how they handle information.
• Best practices for transactional emails: Follow industry best practices for transactional email content, keeping it concise, relevant, and free of anything that could be mistaken for spam or phishing attempts.