Summary
To resolve email delivery issues with Cox, Optimum, and Charter/Spectrum, a multifaceted approach is needed. Key elements include implementing strong email authentication (SPF, DKIM, DMARC) and ensuring SPF records accurately reflect sending sources. Maintaining excellent list hygiene by regularly cleaning lists and avoiding spam traps is crucial. Proactive sender reputation management, including monitoring Sender Score and using Google Postmaster Tools, is essential. Gradual IP warming is recommended for new IPs. Ensuring a correct reverse DNS (PTR) record is also critical. Regular email testing for content and rendering issues can prevent spam filter triggers. List segmentation based on engagement enhances deliverability. Avoiding spam trigger words and excessive formatting is important. Seeded testing and feedback loop (FBL) monitoring provide valuable insights. Specifically, note that Cox uses Cloudmark, their filtering is dynamic, and contacting their support through the Cloudmark form can be beneficial. Additionally, staying within Outlook.com sending limits and monitoring blocklists like Spamhaus are essential.
Key findings
- Authentication: Implement SPF, DKIM, and DMARC for robust email authentication.
- List Hygiene: Maintain clean email lists by removing invalid addresses and avoiding spam traps.
- Sender Reputation: Proactively manage sender reputation, monitoring Sender Score and using tools like Google Postmaster Tools.
- IP Warming: Gradually warm up new sending IPs to build a positive reputation.
- Reverse DNS (PTR): Ensure a correct reverse DNS record maps your sending IP to your domain.
- Content Testing: Regularly test email content to avoid triggering spam filters.
- List Segmentation: Segment your email list based on engagement for better targeting.
- Spam Trigger Avoidance: Avoid spam trigger words and excessive formatting.
- Seeded Testing & FBLs: Use seeded testing and monitor feedback loops (FBLs) for insights.
- Cox-Specific Actions: Understand Cox uses Cloudmark, has dynamic filtering, and offers support via a Cloudmark form.
- Sending Limits: Adhere to sending limits for providers like Outlook.com.
- Blocklist Monitoring: Monitor and address any listings on blocklists like Spamhaus.
Key considerations
- Cloudmark Influence: Cox, Optimum, and Charter/Spectrum rely on Cloudmark for spam filtering, making their rules important to understand.
- Dynamic Filtering: Cox employs dynamic filtering policies that assess reputation continuously.
- Proactive Support: Leverage the Cloudmark support form for issue reporting and clarification with Cox.
- Comprehensive Approach: Deliverability is a complex issue; a comprehensive strategy addressing multiple factors yields the best results.
- Ongoing Monitoring: Email deliverability requires continuous monitoring and adjustments to stay ahead of evolving spam filtering techniques.
What email marketers say
10 marketer opinions
To resolve email delivery issues with Cox, Optimum, and Charter/Spectrum, it's essential to focus on several key areas. These include authenticating your emails using SPF, DKIM, and DMARC; maintaining a clean email list by removing invalid addresses and managing spam complaints; building and monitoring your sender reputation; warming up new IPs gradually; ensuring you have a reverse DNS record; testing your emails for content and rendering issues; segmenting your email list based on engagement; and avoiding spam trigger words and excessive formatting in your email content. For Cox specifically, understand their dynamic filtering policies and use the Cloudmark support form to report issues. Monitoring Sender Score is crucial. Also, consider that Cox assesses reputation dynamically using various metrics.
Key opinions
- Authentication: Implement SPF, DKIM, and DMARC to authenticate your emails and prove legitimacy to ISPs.
- List Hygiene: Regularly clean your email list to remove invalid or inactive addresses and manage spam complaints.
- Sender Reputation: Monitor and maintain a good sender reputation, as it significantly impacts deliverability.
- IP Warming: Gradually warm up new sending IPs to build a positive sending reputation.
- Reverse DNS: Ensure you have a reverse DNS record that maps your sending IP address back to your domain name.
- Content and Testing: Test your emails for content and rendering issues to avoid triggering spam filters and ensure proper display.
- Segmentation: Segment your email list based on engagement to send relevant content to subscribers.
- Spam Triggers: Avoid using spam trigger words and excessive formatting in your email content.
- Cox Specifics: Understand Cox's dynamic filtering policies and utilize the Cloudmark support form to report delivery issues.
Key considerations
- Cloudmark Filtering: Cox, Optimum, and Charter/Spectrum use Cloudmark for spam filtering. Address issues through their support.
- Dynamic Policies: Cox uses dynamic rules/policies that assess reputation on an ongoing basis; monitor closely and adjust sending practices as needed.
- Reputation Metrics: Cox evaluates sending IPs based on various reputation metrics, not just spam complaints.
- SenderScore Monitoring: Actively monitor your Sender Score and address factors impacting it.
Marketer view
Marketer from Email Geeks clarifies that at Cox, it's not necessarily IPs being blocked, but reputation being assessed across different metrics. They advise reducing sending volume/IPs if hitting limits and offer to investigate with provided IPs and rejection messages.
30 Oct 2022 - Email Geeks
Marketer view
Marketer from Email Geeks explains that Cox's filtering is a dynamic set of rules/policies where an IP can change state during an SMTP transaction. Suggests submitting issues via the Cloudmark support form, including rejection messages, timestamps, sending IPs, and destination network/domain.
29 Aug 2024 - Email Geeks
What the experts say
3 expert opinions
To resolve email delivery issues with Cox, Optimum, and Charter/Spectrum, experts recommend using seeded testing to monitor deliverability across various ISPs to identify placement issues and authentication problems. Maintaining clean email lists to avoid spam traps is also essential. Furthermore, setting up and monitoring feedback loops (FBLs) from ISPs is crucial for identifying and addressing deliverability issues, providing valuable data on complaints and abuse reports to improve sender reputation.
Key opinions
- Seeded Testing: Using seeded testing helps identify deliverability issues at specific ISPs, including placement and authentication problems.
- List Cleaning: Maintaining a clean email list is crucial to avoid spam traps and ensure emails are sent to engaged recipients.
- Feedback Loops (FBLs): Setting up and monitoring FBLs provides valuable data on complaints and abuse reports, allowing for quick removal of problematic subscribers.
Key considerations
- Proactive Monitoring: Regularly monitor deliverability using seeded testing to identify issues before they significantly impact sending reputation.
- List Hygiene Practices: Implement a robust list cleaning process to remove invalid or inactive addresses and minimize the risk of hitting spam traps.
- FBL Implementation: Prioritize setting up FBLs with major ISPs to receive timely feedback on subscriber complaints and take corrective actions.
Expert view
Expert from Word to the Wise, Dennis Dayman, answers that setting up and monitoring feedback loops (FBLs) from ISPs is crucial for identifying and addressing deliverability issues. FBLs provide valuable data on complaints and abuse reports, allowing senders to quickly remove problematic subscribers and improve their sending reputation with ISPs like Cox.
23 Jul 2021 - Word to the Wise
Expert view
Expert from Spam Resource, Steve Jones, emphasizes the importance of maintaining clean email lists to avoid hitting spam traps. Regularly cleaning your list to remove invalid or inactive addresses helps ensure that you are only sending to engaged recipients, reducing the likelihood of being flagged as spam by ISPs like Cox.
18 Apr 2023 - Spam Resource
What the documentation says
5 technical articles
To resolve email delivery issues with Cox, Optimum, and Charter/Spectrum (and other ISPs), it's critical to authenticate your email using SPF, DKIM, and DMARC. Ensure your SPF records accurately list authorized sending sources. Implement DMARC to protect against email spoofing. Monitor sender reputation using tools like Google Postmaster Tools. Adhere to email sending best practices, including list management and sending frequency. Stay within sending limits for services like Outlook.com. Regularly check and address any listings on blocklists like Spamhaus.
Key findings
- Email Authentication: Implement SPF, DKIM, and DMARC for proper email authentication.
- Accurate SPF Records: Ensure SPF records accurately list all authorized sending sources.
- Sender Reputation Monitoring: Monitor sender reputation via Google Postmaster Tools and other available services.
- Sending Best Practices: Adhere to email sending best practices, including list management and sending frequency.
- Sending Limits: Stay within sending limits for email providers like Outlook.com.
- Blocklist Monitoring: Monitor and address any listings on blocklists like Spamhaus.
Key considerations
- Authentication Importance: Without proper authentication (SPF, DKIM, DMARC), emails are more likely to be flagged as spam.
- SPF Record Accuracy: Incorrect SPF records can lead to delivery issues, especially with ISPs that check SPF.
- DMARC Benefits: DMARC builds on SPF and DKIM to protect against email spoofing and ensures correct handling of authentication failures.
- Sending Limits Awareness: Exceeding sending limits for providers like Outlook.com can negatively impact deliverability across all ISPs.
- Blocklist Impact: Being listed on blocklists like Spamhaus significantly reduces deliverability.
Technical article
Documentation from Spamhaus details how to check if your IP address is on their blocklist and what steps to take to delist if you have been listed. Monitoring and quickly addressing any listing on Spamhaus can prevent deliverability problems.
19 Jul 2023 - Spamhaus
Technical article
Documentation from Google advises bulk senders to authenticate their email with SPF, DKIM, and DMARC. It also suggests monitoring sender reputation via Google Postmaster Tools and following best practices for list management and sending frequency to avoid delivery issues with ISPs.
28 Sep 2022 - Google
