Why are subscribers automatically unsubscribing without their knowledge?

Summary

Subscribers are automatically unsubscribed without their knowledge due to a confluence of technical, behavioral, and infrastructural factors. Microsoft O365, aggressive spam filters, graymail filters, and security software often take actions that the user hasn't initiated. Technical causes include improperly implemented one-click unsubscribe features, filters following links, especially using GET requests which are triggered by bots, broken unsubscribe links, and PII exposure. Behavioral aspects involve recipients marking emails as spam (triggering feedback loops and EOP actions) when they lack preference management options or receive transactional emails after unsubscribing from marketing lists. Poor list hygiene (failure to remove inactive addresses) and a negative shared IP reputation further contribute to automatic unsubscriptions. Properly aligning email authentication, regular list cleaning, careful unsubscribe link implementation (avoiding GET), monitoring complaint rates, and providing preference centers are key to mitigating these issues.

Key findings

  • Microsoft O365 & Filters: Microsoft O365, aggressive spam filters, and graymail filters automatically unsubscribe users.
  • One-Click & GET: Improperly implemented one-click unsubscribe and using HTTP GET requests in unsubscribe links trigger unwanted actions.
  • Broken Links & Security: Broken unsubscribe links and security software can automatically trigger unsubscriptions.
  • Spam Marking & FBLs: Recipients marking emails as spam triggers feedback loops and automated unsubscriptions.
  • Poor Hygiene & Shared IPs: Poor list hygiene and negative shared IP reputation lead to automatic unsubscriptions.
  • Preference Centers: Lack of preference centers leads to users marking email as spam.

Key considerations

  • Authentication Alignment: Ensure proper SPF, DKIM, and DMARC authentication.
  • List Hygiene Practices: Regularly clean your email lists, removing inactive or bounced addresses.
  • Unsubscribe Link Implementation: Carefully implement unsubscribe links, avoiding HTTP GET requests and ensuring proper functionality.
  • Feedback Loop Management: Monitor and manage feedback loops to address spam complaints promptly.
  • Provide Preference Options: Offer subscribers a preference center to manage their subscriptions.
  • Dedicated IPs: Consider using a dedicated IP address to manage your sender reputation.
  • Address PII: Avoid putting the email address in the URL when using HTTP GET.
  • Monitor Complaint Rates: Monitor and proactively address causes for spam complaints.

What email marketers say
12Marketer opinions

Subscribers may be automatically unsubscribed without their knowledge due to a variety of factors. These include aggressive spam filters unsubscribing based on triggers, recipients marking emails as spam, and poor list hygiene practices leading ESPs to automatically unsubscribe recipients. Issues related to unsubscribe links, like using GET requests or broken links, also contribute. Additionally, shared IP addresses, aggressive spam filters or graymail filters, or even security software can trigger unintended unsubscribes. Microsoft O365 may also initiate unsubscribes. Furthermore, not providing clear email preference options may cause users to mark emails as spam, leading to automatic unsubscriptions. Properly aligning email authentication is key to avoiding these issues. Regularly cleaning email lists and ensuring proper GET/POST use is critical as well.

Key opinions

  • Microsoft O365: Microsoft O365 may automatically unsubscribe recipients, especially if authentication isn't properly aligned.
  • GET Requests: Using GET requests in unsubscribe links can cause unintended unsubscribes due to bot activity and privacy concerns.
  • List Hygiene: Poor list hygiene, such as not removing inactive addresses, leads ESPs to automatically unsubscribe recipients.
  • Complaint Rate: A high complaint rate prompts ESPs to automatically unsubscribe users to protect their reputation.
  • Spam Filters: Aggressive spam filters may automatically unsubscribe users based on keyword detection or sender reputation.
  • Broken Links: Broken or incorrect unsubscribe links can lead email clients to automatically unsubscribe users.
  • Security Software: Security software may automatically click unsubscribe links, causing unintended unsubscribes.
  • Preference Centers: Lack of clear email preference options may cause users to mark emails as spam, triggering automatic unsubscriptions.
  • Shared IP: Using a shared IP address with a poor reputation can cause ESPs to automatically unsubscribe recipients.

Key considerations

  • Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) to improve deliverability and prevent unintended unsubscribes.
  • List Management: Regularly clean your email list to remove inactive, bounced, and unengaged subscribers.
  • Unsubscribe Process: Implement a clear and easy unsubscribe process, avoiding GET requests and ensuring links are functional.
  • Preference Centers: Provide subscribers with a preference center to manage their email subscriptions.
  • Monitor Complaints: Monitor complaint rates and address any issues to maintain a positive sender reputation.
  • Dedicated IP: Consider using a dedicated IP address to control your sending reputation.
Marketer view

Marketer from Email Geeks warns to beware of the fact that many/sometimes unsubscribe links that work with HTTP GET requests, put the plain text email address in the URL parameters. This then gets picked up by various analytics/tracking systems and of course is PII, which likely violates certain consumer rights and vendor agreements. If ever you see an email address in the URL, it’s a slippery slope, at least for European audiences.

January 2023 - Email Geeks
Marketer view

Email marketer from Email Marketing Forum explains that if using a shared IP address, the sending reputation can be affected by other users. If the shared IP is flagged for spam, it can cause ESPs to automatically unsubscribe recipients from emails sent using that IP, even if the sender is following best practices.

April 2023 - Email Marketing Forum
Marketer view

Email marketer from StackExchange shares that some security software or browser extensions might automatically click unsubscribe links as a security measure, without the user's explicit consent. This prevents potential phishing or malicious content from being delivered.

June 2021 - StackExchange
Marketer view

Marketer from Email Geeks says they also saw those GET requests from Microsoft IPs, for emails sent to Office365 mailboxes.

November 2024 - Email Geeks
Marketer view

Email marketer from ActiveCampaign shares that if subscribers are not given clear options to manage their email preferences (via a preference center), they may simply mark emails as spam to stop receiving them. This can lead to automatic unsubscribes triggered by the ESP.

December 2021 - ActiveCampaign
Marketer view

Email marketer from NeilPatel.com shares that sometimes subscribers are automatically unsubscribed if a list isn't regularly cleaned. Inactive subscribers, or those who haven't engaged recently, might be removed to maintain list health and improve deliverability, and these users may not realize they were unsubscribed.

August 2022 - NeilPatel.com
Marketer view

Marketer from Email Geeks shares they have seen Microsoft do this - as in recipients using O365 where the recipients have no knowledge of the unsubscribe and aligning authentication usually fixes it.

April 2023 - Email Geeks
Marketer view

Email marketer from Sendinblue answers that a high complaint rate can lead ESPs to automatically unsubscribe users to protect their reputation. Subscribers who mark emails as spam are essentially unsubscribing themselves without knowing the full implications.

September 2023 - Sendinblue
Marketer view

Email marketer from Email on Acid answers that if the unsubscribe link is broken or directs to an error page, some email clients may interpret this as a request to unsubscribe and do so automatically to improve user experience.

June 2023 - Email on Acid
Marketer view

Marketer from Email Geeks explains the technical difference between a GET and POST is that a GET request is encoded as part of the URL while a POST request is encapsulated in the HTTP request. So any single-action URL (such as a list-unsubscribe link) has to be a GET because it's only a single link and all of the info has to be there. However, what happens when the call is made (update a table, unsubscribe an address) is completely up to the programmer. POST is usually a better choice chiefly because the data can be protected by SSL and is not publicly visible in the URL. Most web forms use POST. However, because you can't encode a POST within a URL, GET has its place too.

July 2023 - Email Geeks
Marketer view

Email marketer from Litmus shares that poor list hygiene practices, such as not regularly removing bounced or inactive addresses, can lead to ESPs automatically unsubscribing recipients. ESPs do this to protect their own reputation and deliverability rates.

December 2022 - Litmus
Marketer view

Email marketer from Reddit shares that some aggressive spam filters might automatically unsubscribe users based on certain triggers, like keyword detection or sender reputation. These unsubscribes happen server-side, without the recipient's direct action.

June 2023 - Reddit

What the experts say
6Expert opinions

Automatic, unknown unsubscriptions stem from filtering systems following unsubscribe links, especially with one-click unsubscribe and HTTP GET requests. Feedback loops (FBLs), where marking emails as spam triggers automated unsubscriptions to prevent further complaints, also contribute. Graymail filtering, identifying emails users no longer want and unsubscribing them automatically, is another factor. Providers also unsubscribe users flagged for sending abusive emails to protect their customers.

Key opinions

  • Filtering Systems: Filters follow unsubscribe links, causing unintended unsubscriptions.
  • One-Click Unsubscribe: One-click unsubscribe, while convenient, increases the risk of non-human clicks causing unsubscriptions.
  • HTTP GET: Improper HTTP GET implementation in unsubscribe links triggers automated unsubscribes.
  • Feedback Loops (FBLs): Marking emails as spam triggers automated unsubscriptions through FBLs.
  • Graymail Filtering: Systems automatically unsubscribe users from graymail lists (emails no longer wanted).
  • Abuse Reporting: Mail providers automatically unsubscribe users flagged for sending abusive or spam emails.

Key considerations

  • Monitor Filtering: Be aware of how filtering systems might interact with unsubscribe links.
  • Avoid One-Click: Carefully consider the use of one-click unsubscribe due to potential for unintended clicks.
  • Implement HTTP Correctly: Ensure proper implementation of HTTP GET/POST methods in unsubscribe links.
  • Manage FBLs: Monitor feedback loops and address spam complaints promptly.
  • Segment Graymail: Implement strategies for segmenting and engaging graymail recipients before they unsubscribe.
  • Prevent Abuse: Adhere to email best practices to avoid being flagged for sending abusive or spam emails.
Expert view

Expert from Email Geeks explains if clicking on that link creates an automatic unsubscribe in your system, then, yes, it will. the Get/Post thing is something in http. as i understand it (and my understanding is shakey at best) one of those types of http calls immediately changes the underlying data and has an effect (so if any URL checker follows the link the address is immediately unsubscribed from the mail) the other type of http call does not immediately change the server data, so simply following the link does not result in the underlying data (so when a URL checker follows the link the address is not unsubscribed from the mail).

January 2025 - Email Geeks
Expert view

Expert from Spam Resource explains that feedback loops (FBLs) can cause automatic unsubscribes. If recipients mark emails as spam, this information is sent back to the sender through the FBL. Some email systems are configured to automatically unsubscribe recipients who trigger the FBL to prevent further spam complaints.

October 2023 - Spam Resource
Expert view

Expert from Email Geeks explains this is one of the reasons they do not recommend one-click unsubscribe - non-human clicks that end up unsubscribing.

November 2023 - Email Geeks
Expert view

Expert from Word to the Wise (Laura Atkins) explains that some filtering systems identify 'graymail' (emails that users may have opted into but no longer want) and automatically unsubscribe users from these lists. This can happen without the user explicitly requesting to unsubscribe.

July 2022 - Word to the Wise
Expert view

Expert from Spam Resource explains that, when users mark a message as abusive or spam, some mail providers use this information to automatically unsubscribe the user to prevent further abusive emails from being sent to that user. This is one way to protect their customer base from unwanted communications.

May 2022 - Spam Resource
Expert view

Expert from Email Geeks suggests that it’s very likely that the subscribers are all customers of one filtering system or another and the filters are following all the links in your emails.

August 2021 - Email Geeks

What the documentation says
4Technical articles

Subscribers are automatically unsubscribed without their knowledge due to several documented reasons. Google Support highlights that improper implementation of one-click unsubscribe in Gmail can lead to filters or Gmail initiating the unsubscribe. The RFC Editor notes that using HTTP URLs with GET requests in the List-Unsubscribe header improperly can cause bots to trigger unintended unsubscribes. Microsoft explains that Exchange Online Protection (EOP) may automatically unsubscribe recipients with high complaint volumes. Mailchimp points out that if a recipient unsubscribes from a marketing list but still receives transactional emails, they may report them as spam, triggering automated unsubscriptions from all lists.

Key findings

  • Gmail One-Click: Improper one-click unsubscribe implementation can lead to automatic unsubscriptions by Gmail.
  • HTTP GET: Using HTTP GET requests in List-Unsubscribe headers improperly can cause unintended bot-triggered unsubscriptions.
  • Exchange Online Protection (EOP): EOP may automatically unsubscribe recipients with high complaint volumes to protect users.
  • Transactional Emails: Sending transactional emails to users unsubscribed from marketing lists can trigger spam reports and automated unsubscriptions from all lists in Mailchimp.

Key considerations

  • One-Click Implementation: Properly implement Gmail's one-click unsubscribe feature.
  • Unsubscribe Method: Avoid using HTTP GET requests in List-Unsubscribe headers; prefer POST requests.
  • Complaint Monitoring: Monitor complaint rates and address negative signals to prevent automatic unsubscriptions by EOP.
  • List Segmentation: Segment marketing and transactional email lists to avoid sending unwanted emails to unsubscribed users.
Technical article

Documentation from Google Support explains that Gmail supports one-click unsubscribe, where users can unsubscribe directly from the Gmail interface. If a sender doesn't properly implement this, filters or Gmail itself might initiate the unsubscribe process on behalf of the user.

January 2023 - Google Support
Technical article

Documentation from RFC Editor explains that the List-Unsubscribe header can be implemented with either a mailto: or an HTTP URL. If using HTTP, improper configuration, like using a GET request that automatically unsubscribes upon being crawled by a bot, can cause unintended unsubscribes.

April 2023 - RFC Editor
Technical article

Documentation from Microsoft explains that Exchange Online Protection (EOP) may automatically unsubscribe recipients from mailing lists if it detects a high volume of complaints or other negative signals. This is done to protect users from unwanted emails.

March 2024 - Microsoft
Technical article

Documentation from Mailchimp explains that if a recipient is unsubscribed from a marketing list but still receives transactional emails, they might report the emails as spam. This can trigger automated unsubscribes from all lists, even if the recipient intended to only unsubscribe from the marketing list.

June 2021 - Mailchimp

No related resources found.