How to troubleshoot and resolve soft bounce issues with Yahoo/VZG email delivery?
Matthew Whittaker
Co-founder & CTO, Suped
Published 9 May 2025
Updated 19 Aug 2025
6 min read
Dealing with soft bounce issues, particularly with Yahoo and VZG (Verizon Media Group, which includes Yahoo and AOL), can be one of the most frustrating challenges in email delivery. Unlike hard bounces that indicate a permanent delivery failure, soft bounces (also known as deferrals) suggest a temporary problem. The email server couldn't deliver the message immediately, but it might try again later. While this sounds less severe, persistent soft bounces can severely impact your sender reputation and overall inbox placement, leading to a de facto block or blacklist.
My experience shows that many factors contribute to these deferrals. Sometimes, it’s a simple issue like a full inbox, but more often, it points to deeper problems with your sending practices or the content you're sending. Yahoo and VZG email servers are known for their stringent filtering, and they’re quick to defer mail if anything seems amiss, even if it's not an outright spam indication.
Understanding why these temporary rejections occur is the first step toward resolution. I've found that these issues often stem from how recipient servers perceive your sending patterns and content, rather than just basic authentication failures. Let's delve into the common causes and how to effectively troubleshoot and resolve these soft bounce challenges.
The subtleties of Yahoo/VZG email filtering
Yahoo and VZG, like many major email providers, employ sophisticated systems to evaluate incoming mail. They don't just look at basic authentication, but also scrutinize the sender's reputation, the email content, and the engagement of the recipients. A soft bounce, or temporary deferral, is their way of saying, 'We're not sure about this mail right now, try again later.' Repeated deferrals from the same sender or content will often lead to eventual hard blocks or being placed on a blocklist (or blacklist).
How VZG evaluates emails
VZG's systems perform a deep analysis of every message. This includes looking at links within the email, the overall structure of the content, and even pattern matching on images. It’s a comprehensive scan designed to identify potential spam or unwanted mail before it reaches the inbox. If anything in this analysis raises a flag, a soft bounce can occur.
Content Scan: They inspect not just the text, but also the nature of links, image patterns, and overall message composition.
Sender Reputation: Your domain and IP reputation are constantly assessed based on past sending behavior, spam complaints, and engagement metrics.
List Quality: Sending to unengaged or old addresses significantly increases soft bounces, as these can be indicators of poor list management.
A crucial point to grasp is that VZG (and other providers) see the full message before a temporary failure. This means they are analyzing everything from the embedded links to the images. If you're encountering persistent deferrals, especially with VZG, it's often a signal that your mail is not wanted, and a deeper compliance investigation is warranted. You need to identify why their filters are flagging your mail.
When facing soft bounces from Yahoo/VZG, the primary suspect often lies with the quality of your recipient list. My observations consistently point to senders not removing stale or non-responsive email addresses quickly enough. Continuing to send to old, unengaged recipients is a major red flag for ISPs.
Problem: poor list hygiene
Sending to an email list filled with outdated, inactive, or unengaged addresses drastically increases your chances of soft bounces and impacts your sender reputation. ISPs, including Yahoo and Google, interpret this as a sign that your mail is unwanted or that you are not managing your list effectively. This can lead to your emails being deferred or even outright blocked.
Solution: rigorous list cleaning
Implement a strict process for cleaning your email lists. Actively suppress addresses that show no engagement after a certain period (e.g., 90-120 days). Pay close attention to soft bounces and remove addresses that consistently defer. Tools for list validation can also help identify and remove problematic addresses before you even send to them.
I’ve seen this pattern countless times: senders who clean their lists regularly tend to have fewer problems with major providers, especially Yahoo and AOL. Conversely, those who delay in culling unengaged recipients often face significant soft bounce rates and poor inbox placement overall. Your deliverability is only as good as the quality of your list.
While list quality is paramount, the technical aspects of your email content and infrastructure can also trigger soft bounces. VZG examines the entire message, including the domains of linked content and images. This means that issues with your content delivery network (CDN) or even seemingly innocuous elements like image hosting can cause problems.
I recall a client who experienced two months of delivery problems that vanished only when they realized the issues coincided with a CDN change. This highlights that external resources referenced in your emails can affect deliverability. If a CDN is compromised or has a poor reputation, VZG's filters might associate that negative standing with your email.
Furthermore, VZG's ability to pattern match images and other assets, regardless of their hosting location, is a sophisticated defense against spam. Spammers often use image-only emails to bypass text filters. Over time, ISPs have developed defenses against this, applying image analysis to all mail. This means even if your images are legitimate, their composition or similarity to known spam patterns can lead to deferrals. Be mindful of image size, ratio, and embedded elements.
Example of content with external assetsHTML
<img src="https://static.example.com/images/promo_banner_xyz.png" alt="Promotional Banner" style="width:100%; max-width:600px;">
<a href="https://www.example.com/product-link-xyz">Click here for our new product!</a>
Beyond list hygiene and content scrutiny, there are several proactive measures you can take to mitigate and resolve soft bounce issues with Yahoo/VZG. These largely revolve around consistent monitoring and adhering to email sending best practices.
Regularly monitor your bounce logs and analyze the specific error codes. For Yahoo and VZG, common soft bounce codes might include 4xx SMTP responses. These indicate temporary failures, but the specific sub-code can offer clues as to the underlying issue. Keep an eye on your sending reputation using any available postmaster tools. For Yahoo, this helps you understand their perception of your sending domain and IP addresses.
Ensure your email authentication records, including SPF, DKIM, and DMARC, are correctly configured. While often associated with hard bounces or spam folder delivery, misconfigurations can also contribute to temporary deferrals as ISPs struggle to verify your identity. Strong authentication builds trust, which is crucial for passing VZG's filters.
If you're using shared IP space, be aware that the sending practices of others on the same IP can affect your deliverability. If they send problematic content or to poor lists, your mail can suffer. If you are a high-volume sender, consider dedicated IPs to gain more control over your sending reputation and reduce the risk of being affected by other senders.
Views from the trenches
Best practices
Maintain an active and engaged email list, regularly removing subscribers who have not interacted with your emails for an extended period.
Segment your audience and tailor content to ensure relevance, reducing the likelihood of disengagement and spam complaints.
Monitor your bounce logs meticulously for specific Yahoo/VZG error codes to pinpoint underlying issues.
Ensure all email authentication protocols, including SPF, DKIM, and DMARC, are correctly implemented and aligned.
Common pitfalls
Neglecting to remove unengaged or inactive subscribers, which signals poor list hygiene to ISPs and impacts sender reputation.
Failing to review the full email message, including images and CDN-hosted content, which can be flagged by sophisticated filters.
Ignoring specific soft bounce codes (deferrals), as these temporary failures often indicate underlying issues that need immediate attention.
Assuming that good deliverability with other providers like Google or Microsoft guarantees similar results with Yahoo/VZG, which have unique filtering.
Expert tips
Consider a dedicated IP address for high-volume sending to gain greater control over your sender reputation and avoid issues from other senders.
If using a CDN for images or other content, ensure its reputation is clean, as VZG deeply inspects all linked domains and content.
Implement feedback loops where possible to automatically remove users who mark your emails as spam, preventing future issues.
Engage with Yahoo's postmaster tools or support if consistent deferrals persist, providing concrete data for their review.
Expert view
Expert from Email Geeks says a sender's list quality is often the primary reason for these delivery issues, and tightening up lists tends to resolve them.
September 24, 2020 - Email Geeks
Expert view
Expert from Email Geeks says that looking closely at infrastructure is important because VMG analyzes the full message, including links and content from CDNs, before a temporary failure.
September 24, 2020 - Email Geeks
Our path to better deliverability
Resolving soft bounce issues with Yahoo/VZG requires a multifaceted approach focused on maintaining excellent sender reputation, rigorous list hygiene, and diligent content review. Temporary deferrals are not to be ignored, as they are often early warnings of deeper problems that can lead to permanent blocks.
By actively managing your recipient lists, scrutinizing your email content for anything that might trigger VZG's sophisticated filters, and proactively monitoring your deliverability metrics, you can significantly improve your inbox placement rates and ensure your messages reliably reach their intended audience. The goal is to build and maintain trust with these major email providers.
Yahoo and 
Google, interpret this as a sign that your mail is unwanted or that you are not managing your list effectively. This can lead to your emails being deferred or even outright blocked.
