Why am I seeing increased email bounces at AT&T?

Key findings

• Observed spikes: Senders frequently report noticeable, abrupt increases in bounces from AT&T domains, sometimes resolving within a day or two.
• Common bounce codes: Typical bounce messages include 5.7.9 Message not accepted for policy reasons or DNSBL:RBL _is_blocked, indicating policy enforcement or blocklist (blacklist) issues.
• Internal issues: AT&T may experience temporary, widespread blocking due to their own system problems or a response to large spam waves, affecting many legitimate senders.
• Support contact: Emailing is a common first step, though auto-responses are typical initially.

Key considerations

• Monitor bounce codes: Carefully analyze the specific bounce codes from AT&T to understand whether the issue is related to general policies, blocklistings, or other factors.
• Check reputation: Regularly check your sending IP and domain reputation on public blocklists (blacklists) to ensure your sending infrastructure is not compromised.
• Contact support: If bounces persist, you may need to reach out to AT&T email customer support for further assistance, especially if your account was flagged.
• Review authentication: Ensure your email authentication protocols like SPF, DKIM, and DMARC are correctly configured. Issues with these can lead to rejections from ISPs. For more information, see why AT&T might be blocking your emails. Also consider reading why AT&T email domains experience block bounces.

Key opinions

• Increased blocking: Many marketers report a clear and sudden increase in AT&T blocking, often occurring around the same time for multiple senders.
• Temporary nature: A common observation is that these blockages can be temporary, sometimes resolving within a day or two without direct intervention.
• Bounce code consistency: Some marketers note consistent bounce codes, such as 5.7.9 Message not accepted for policy reasons, suggesting a policy-based rejection.
• DNSBL issues: Others report bounces explicitly mentioning DNSBL (DNS Blocklist) with a specific error code, indicating an IP or domain blocklisting.
• Support challenges: Marketers often receive automated responses when submitting tickets to AT&T's abuse desk.

Key considerations

• Collect bounce data: It is vital to gather specific bounce codes and messages to accurately diagnose the problem.
• Community insights: Engage with the email community to determine if others are experiencing similar issues, which can indicate a broader ISP problem.
• Verify blocklists: Even if an ISP-wide issue is suspected, it is always wise to check your sending IP against common email blocklists. For specific AT&T bounces, also read about high bounce rates to AT&T, SBC, and Bellsouth.
• Patience: Given the often temporary nature of these issues, a period of observation after reporting can sometimes be sufficient for resolution. A related discussion can be found on Constant Contact Community.

Key opinions

• ISP-side issues: Experts confirm that sudden, widespread blocking by AT&T often stems from internal system adjustments or their response to detected spam waves, rather than solely individual sender reputation problems.
• Temporary blocks: It is often noted that these significant increases in bounces can be temporary, with delivery sometimes returning to normal within a short period.
• Limited communication: While AT&T (via Yahoo) may be aware of issues, direct, specific communication with senders beyond automated responses is often minimal.
• Authentication importance: Strong email authentication (SPF, DKIM, DMARC) is consistently highlighted as a foundational element for maintaining deliverability, especially when facing ISP-specific challenges.
• Spam wave impact: Large-scale spam campaigns can trigger aggressive filtering at ISPs, leading to collateral damage for legitimate senders, as seen when AT&T delayed Microsoft 365 emails.

Key considerations

• Leverage postmaster tools: Use Yahoo Postmaster Tools (which covers AT&T) to gain insights into your sending reputation and delivery trends specific to their network. Consider using our guides, for example, on DMARC, SPF, and DKIM.
• Check public blacklists (blocklists): Even if the issue seems widespread, always verify your IP and domain against major public blacklists (blocklists). For more information, see what an email blacklist (blocklist) is.
• Strategic retries: Avoid aggressive retry schedules for persistently bouncing messages, as this can negatively impact your sender reputation with the ISP.
• Proactive support: While responses may be automated, submitting support tickets via the Yahoo Postmaster portal is the official channel for reporting and potentially resolving issues related to AT&T deliverability.

Key findings

• Policy rejections: Bounce codes like 5.7.9 explicitly mean the message was not accepted due to a receiving server's policy.
• Blocklist (blacklist) listings: Errors referencing DNSBL indicate that the sending IP or domain is listed on a blocklist.
• Account security: If an email account is flagged for spam, it may be deactivated, necessitating direct contact with the ISP's support for reactivation.
• Invalid addresses: A common cause for hard bounces is an invalid or non-existent recipient email address.
• Authentication failures: Lack of proper SPF, DKIM, or DMARC authentication can lead to emails being rejected for security reasons.

Key considerations

• Understand bounce types: Familiarize yourself with the various types of email bounces and their corresponding error codes to accurately diagnose issues.
• Implement authentication: Ensure your domain has correctly configured SPF, DKIM, and DMARC records to prove legitimate sending. See our list of DMARC tags, and how to fix common DMARC issues.
• Adhere to postmaster guidelines: Consult the postmaster pages of major ISPs like AT&T (via Yahoo) for specific guidelines on acceptable sending practices and troubleshooting. AT&T provides email support articles on resolving email issues.
• Clean lists: Regularly clean your email lists to remove invalid or inactive addresses, which helps reduce bounce rates and maintain a good sender reputation.