Why does Gmail List-Unsubscribe only work on the second attempt?
Michael Ko
Co-founder & CEO, Suped
Published 3 May 2025
Updated 13 Oct 2025
8 min read
It can be frustrating when you or your recipients try to unsubscribe from an email list, only to find that Gmail's handy unsubscribe button seems to fail on the first attempt, requiring a second click to finally process the request. This isn't just an inconvenience, it's a critical deliverability issue that can impact sender reputation and lead to increased spam complaints. I've seen this exact scenario play out for many email senders, and it usually boils down to a few key technical details related to how the List-Unsubscribe header is implemented.
Understanding the nuances of how Gmail's unsubscribe button works and interacts with the List-Unsubscribe header is essential for ensuring a smooth experience for your subscribers. When the initial one-click unsubscribe fails, it can lead to confusion and a higher likelihood of recipients marking your emails as spam, which negatively affects your sender reputation. The goal is to make unsubscribing as easy and reliable as possible.
In this article, I'll dive into the technical specifics of the List-Unsubscribe header, explain Gmail's expected behavior, and uncover the common pitfalls that lead to the second attempt conundrum. I’ll also provide practical advice on how to configure your email system correctly to avoid this issue, ensuring that your List-Unsubscribe function works reliably every time, and help you maintain a healthy sender reputation.
Understanding the List-Unsubscribe header
The List-Unsubscribe header is a crucial component for modern email deliverability. It's an instruction embedded in the email's header that allows recipients to easily unsubscribe from a mailing list without having to click a link within the email body. This feature is particularly important for major mailbox providers like Gmail and Yahoo, which have recently enforced stricter requirements around one-click unsubscribe.
Traditionally, the List-Unsubscribe header could contain either a mailto address, an HTTP/HTTPS URL, or both. The mailto option triggers an email to be sent to a specific address, indicating an unsubscribe request. The URL option directs the user or the mailbox provider to a web page or an API endpoint to complete the unsubscribe process. While RFC 5322 allows for both, RFC 8058 introduced the List-Unsubscribe-Post header specifically for one-click HTTP POST requests.
The key here is that modern mailbox providers, especially Gmail, prefer the one-click unsubscribe method using an HTTP POST request to a provided URL. This method is considered more reliable and user-friendly than the mailto option, as it doesn't require the recipient to send an email, simplifying the process significantly. When an unsubscribe button appears in Gmail's interface, it's typically trying to trigger this specific POST request.
Gmail is very particular about when and how it displays the unsubscribe button (or link) next to the sender's email address. It’s not simply a matter of including the List-Unsubscribe header; Gmail actively assesses various factors before presenting this convenient option. Critical to this assessment is the sender's reputation.
For Gmail to offer the one-click unsubscribe option, your email program needs to include both the List-Unsubscribe and List-Unsubscribe-Post headers. When a user clicks the unsubscribe button, Gmail first attempts a HTTP POST request to the URL specified in the List-Unsubscribe header, as indicated by the List-Unsubscribe-Post header. This is the desired one-click functionality.
If this POST request fails (for reasons I'll cover shortly), Gmail will often present a second prompt to the user, typically giving them the option to Go to Website. This second action usually triggers an HTTP GET request to the same URL, which might succeed where the POST failed. This fallback mechanism explains why the unsubscribe sometimes works on the second attempt, but it's not ideal for user experience or your reputation.
Reasons for the two-click unsubscribe
The primary culprit behind Gmail's List-Unsubscribe requiring a second attempt is almost always related to the server's handling of HTTP requests. I've personally seen cases where the unsubscribe URL (specified in the List-Unsubscribe header) was configured to block POST requests. When Gmail attempts the one-click unsubscribe via a POST, it fails. The second click, however, often triggers a GET request, which the server then successfully processes.
URL blocking POST requests
The most common reason for the two-click issue is that your unsubscribe URL endpoint does not accept HTTP POST requests. RFC 8058, which governs one-click unsubscribes, mandates that the URL should support POST. If your server is blocking these requests, the first attempt by Gmail will fail silently, prompting the user for a second, often GET-based, interaction.
Another factor could be the absence of a mailto: option in your List-Unsubscribe header. While current best practices prioritize the HTTP POST method, some older systems or fallback mechanisms might still rely on mailto. If only a URI is provided, and the POST fails, it forces Gmail to re-evaluate how it handles the unsubscribe, leading to the second popup with a 'Go to Website' option. It's a less common issue now, but still worth checking.
Problematic List-Unsubscribe
Header configuration: Only includes a URI, or has List-Unsubscribe-Post before List-Unsubscribe.
Server endpoint: Does not accept HTTP POST requests to the unsubscribe URL.
Result: Gmail's one-click unsubscribe fails, requiring a second action (GET request) to complete.
Optimal List-Unsubscribe
Header configuration: Includes both List-Unsubscribe (with URL) and List-Unsubscribe-Post for one-click functionality.
Server endpoint: Accepts and processes HTTP POST requests to the unsubscribe URL.
Result: Gmail's one-click unsubscribe works seamlessly with a single interaction.
Ensuring smooth one-click unsubscribes
To ensure your List-Unsubscribe works correctly on the first attempt, you need to verify your email system and server configurations. The most important step is to confirm that the URL specified in your List-Unsubscribe header is capable of receiving and processing HTTP POST requests. This is critical for supporting the one-click unsubscribe mechanism that Gmail and Yahoo now enforce. You may need to work with your web development or IT team to ensure the endpoint is correctly configured to accept these requests.
I also recommend thoroughly testing your unsubscribe process from various email clients, especially Gmail. Send test emails to a Gmail account and try the unsubscribe button. Observe if it works on the first try or requires a second interaction. This hands-on testing will quickly reveal if the underlying issue has been resolved. Regularly monitoring your sender reputation and deliverability metrics using tools like Google Postmaster Tools is also a good practice, as a poor reputation can influence how Gmail displays the unsubscribe option.
Finally, ensure your email authentication records, such as DMARC, SPF, and DKIM, are correctly configured. These are foundational for building trust with mailbox providers. A robust DMARC policy, especially when monitored with a tool like Suped, provides transparency into your email streams and helps identify any authentication issues that might indirectly affect deliverability, including how unsubscribe headers are perceived.
Views from the trenches
Best practices
Always include both List-Unsubscribe and List-Unsubscribe-Post headers in your emails.
Ensure the URL provided in the List-Unsubscribe header can successfully handle HTTP POST requests.
Test your unsubscribe functionality across various email clients, particularly Gmail, to verify one-click operation.
Common pitfalls
Configuring the unsubscribe URL to block HTTP POST requests, leading to failed one-click unsubscribes.
Not including the List-Unsubscribe-Post header, which is essential for true one-click functionality.
Relying solely on the mailto option, which is less favored by modern mailbox providers for one-click functionality.
Expert tips
Ensure the List-Unsubscribe-Post header is present and the target URL processes POST requests for compliance with RFC 8058.
While header order might not be strictly mandated, consistently placing List-Unsubscribe before List-Unsubscribe-Post can ensure reliability.
Beyond technical headers, continuously engage with your subscribers to maintain positive sending metrics and reduce spam complaints.
Marketer view
Marketer from Email Geeks says a key issue arises when the unsubscribe URL blocks POST requests, causing the initial one-click unsubscribe to fail and forcing a fallback to a GET request via a second popup.
February 27, 2024 - Email Geeks
Expert view
Expert from Email Geeks says Gmail may not display the in-platform unsubscribe button if it doesn't trust the sender's reputation or the link domain's reputation.
February 27, 2024 - Email Geeks
Prioritizing seamless unsubscribes
The phenomenon of Gmail's List-Unsubscribe requiring a second attempt is a clear indicator of a technical misconfiguration, most often related to your unsubscribe URL's ability to handle HTTP POST requests. While Gmail provides a fallback, relying on it degrades user experience and can harm your sender reputation. Prioritizing a seamless, one-click unsubscribe process is not just about compliance, it's about respecting your subscribers and maintaining high deliverability.
By ensuring your List-Unsubscribe headers are correctly implemented, supporting POST requests, and continuously monitoring your email health, you can prevent this two-click scenario. Tools like Suped can provide valuable insights into your email deliverability, helping you troubleshoot and optimize your email program for maximum inbox placement and subscriber satisfaction.
Gmail and 
Yahoo, which have recently enforced stricter requirements around one-click unsubscribe.
