What do abandoned AT&T email addresses mean for your email deliverability?
Matthew Whittaker
Co-founder & CTO, Suped
Published 8 Oct 2025
Updated 8 Oct 2025
7 min read
Recently, there's been discussion about AT&T sending out notices regarding abandoned email addresses, specifically those ending in @att.net, @sbcglobal.net, and similar domains. While some of these notices contained humorous deadline dates, the underlying message is serious for email senders: a significant cleanup of inactive accounts is likely underway. This kind of purge can lead to a surge in bounces if your email lists contain these old addresses.
For email marketers and businesses, abandoned email addresses represent a quiet but persistent threat to deliverability. They can degrade your sender reputation, trigger spam filters, and ultimately reduce the effectiveness of your email campaigns. Understanding what happens to these addresses and how to manage them is crucial for maintaining healthy email sending practices, especially with a major internet service provider like AT&T.
This article explores the implications of abandoned AT&T email addresses for your email deliverability, the risks they pose, and the best strategies to mitigate their impact.
The impact of abandoned AT&T email addresses
AT&T, through its various acquisitions over the years, hosts numerous legacy email domains, including @att.net, @sbcglobal.net, @bellsouth.net, and others. Many users obtained these email addresses as part of their internet service bundles. When customers switch providers or abandon their service accounts, these email addresses often become inactive but can remain in existence for extended periods. This current wave of notices suggests a concerted effort to finally sunset these long-dormant accounts.
When an email address is abandoned due to inactivity, the email provider typically moves it through several stages. Initially, emails sent to these addresses might bounce as soft bounces, indicating a temporary issue. Eventually, if the account remains unused, it gets suspended, and incoming emails are rejected with a hard bounce. A Reddit user mentioned that an email address could be separated and left on its own after an internet service cancellation. This makes it a prime candidate for eventual retirement.
The long-term consequence for email senders is that these addresses, if not properly removed from mailing lists, will consistently generate hard bounces. A high bounce rate is a clear indicator to Internet Service Providers (ISPs) that your list hygiene is poor, which can negatively affect your sender reputation. This is especially true for the various AT&T, SBC, and Bellsouth domains that have been experiencing high bounce rates.
The threat of spam traps and blocklists
One of the most dangerous outcomes of sending to abandoned email addresses is hitting spam traps. A spam trap is an email address that once belonged to a real user but has since been abandoned, reclaimed by the ISP, and repurposed to catch spammers. Sending to such an address indicates that your list is outdated or poorly sourced.
When your emails hit a spam trap, it severely damages your sender reputation. ISPs like AT&T use spam traps to identify senders who are not maintaining their lists, which often correlates with spammy behavior. Hitting even a few can lead to your emails being filtered into spam folders, throttled, or even blocked entirely by ISPs.
Ultimately, repeatedly sending to abandoned email addresses and hitting spam traps can result in your sending IP or domain being placed on a public or private blocklist. This makes it extremely difficult for your legitimate emails to reach the inbox, impacting not only your AT&T recipients but potentially all recipients. Monitoring blocklists through a blocklist monitoring service is essential.
The danger of abandoned accounts
Sending emails to defunct accounts can have severe consequences for your email program:
Increased bounce rates: A clear signal to ISPs that your list quality is low.
Spam trap hits: Directly impacts your sender reputation and can lead to immediate blocking.
Blocklist inclusion: Your emails may not reach anyone, not just AT&T users.
Reduced inbox placement: Legitimate emails end up in spam folders, wasting marketing efforts.
Maintaining a healthy sender reputation
To counter the risks associated with abandoned AT&T email addresses and other inactive accounts, proactive list hygiene is paramount. Regularly cleaning your email list ensures you are only sending to engaged recipients. This improves your overall deliverability and protects your sender reputation.
Implement robust bounce management protocols. Automatically suppress email addresses that result in hard bounces. While soft bounces might indicate temporary issues, consistent soft bounces for an extended period should also lead to removal. Many email service providers (ESPs) handle this automatically, but it is important to monitor your bounce reports. For more details on what bounces indicate, read what mailbox disabled bounces indicate.
Consider implementing a re-engagement strategy for inactive subscribers. Before removing them entirely, try a targeted campaign to verify their interest. For contacts who do not respond, it's safer to remove them from your active sending list. Regular list validation services can also help identify and remove invalid or abandoned addresses before you send to them, ensuring your emails don't fail.
Reactive list management
Waiting for bounces: Only removing addresses after they hard bounce, potentially after damage is done.
Ignoring engagement: Not actively trying to re-engage inactive subscribers before they become problems.
High complaint rates: Increases spam complaints as emails reach uninterested recipients.
Proactive list management
Regular validation: Using tools to verify email addresses and remove invalid ones before sending.
Re-engagement campaigns: Segmenting and targeting inactive users to prevent abandonment.
Bounce & suppression: Automating the removal of hard bounces and unengaged subscribers.
Leveraging DMARC for insight and protection
DMARC (Domain-based Message Authentication, Reporting, and Conformance) plays a critical role in gaining visibility into your email ecosystem and identifying potential deliverability issues. By implementing a DMARC policy, you receive aggregate reports that detail how ISPs, including AT&T, are handling your emails.
These DMARC reports show authentication failures (SPF and DKIM), as well as disposition rates, telling you whether your emails are being delivered, quarantined, or rejected. This data is invaluable for pinpointing specific problems, such as a sudden increase in rejections from AT&T domains that could indicate a list quality issue or a shift in their filtering policies. Understanding these reports is key to improving email deliverability.
We strongly recommend using Suped for DMARC monitoring. Suped offers the most generous free plan available, making it easy to gain complete visibility into your email deliverability. This includes identifying issues with abandoned AT&T addresses and proactively protecting your sender reputation. A simple guide to DMARC, SPF, and DKIM can help you get started.
Example DMARC record to start monitoring (p=none)DNS
The recent AT&T email address cleanup is a timely reminder that maintaining email deliverability requires constant vigilance. Abandoned email addresses, whether AT&T, SBCGlobal, or any other domain, pose a significant threat by becoming spam traps and leading to blocklisting. Implementing proactive list hygiene, robust bounce management, and leveraging DMARC monitoring are essential strategies for any sender looking to protect their sender reputation and ensure their emails reach the inbox. By addressing these issues head-on, you can navigate changes from major ISPs like AT&T and maintain strong email deliverability.
Views from the trenches
Best practices
Regularly audit your email lists for inactive subscribers, especially those on legacy domains.
Implement a clear re-engagement strategy for subscribers who haven't opened emails in a while.
Utilize DMARC reporting to gain insight into how ISPs are handling your email traffic.
Ensure your email platform automatically suppresses hard bounces to prevent future sends.
Segment your audience and tailor content to maintain high engagement rates and reduce abandonment.
Common pitfalls
Continuing to send to old, unengaged email addresses, leading to higher bounce rates.
Failing to monitor DMARC reports for signs of email authentication issues or blockages.
Not having a strategy for re-engaging inactive subscribers before removing them.
Overlooking legacy domains like SBCGlobal.net, which are prone to becoming spam traps.
Relying solely on an ESP's bounce handling without reviewing detailed reports.
Expert tips
"Keep an eye on bounce rates from older domains; a spike could indicate a provider cleanup."
"Regularly cross-reference your subscriber lists with known inactive periods for major ISPs."
"DMARC aggregate reports can reveal unexpected delivery issues from domains like AT&T."
"Focus on quality over quantity for your email list to protect your sender reputation."
"Implement a sunset policy for subscribers who remain unengaged after multiple re-engagement attempts."
Marketer view
A Marketer from Email Geeks says that a recent notice regarding AT&T email addresses suggests a broad transition clean-out, which will likely result in an increase in bounces from previously active but now abandoned accounts.
2024-09-29 - Email Geeks
Marketer view
A Marketer from Email Geeks says that AT&T appears to be targeting older or niche domains, such as sbcglobal.net, for deletion, with notifications being sent even for accounts that have been inactive for over a decade.
