Repairing Your Email Sender Reputation: Understanding Symptoms and Root Causes

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Email deliverability issues can be complex, so how do you know if have an issue with your sender reputation? A poor reputation may result in low deliverability, junk folder placement, lower than normal open rates, bounce messages that refer to volume limits or reputation, a compliance notice from your provider, and of course if your sending domain is blacklisted by an anti-spam/anti-abuse service. Of course it’s not that simple, as most of these issues have other potential causes as well that aren’t strictly reputation related. For example, you could have a great sender reputation and still experience low open rates on a campaign due to an unappealing subject line. Additionally, email that is blocked or junked could be due to improper/missing authentication or the use of spam keywords.  Because of this complexity, it’s hard to say if a delivery issue is solely due to reputation, but you can make sure your reputation is squeaky clean to eliminate it from the equation.  So for the purposes of this guide, let’s assume you’re sending properly authenticated, engaging, non-spam content at consistent volumes, and let’s focus on the remaining factors of sender reputation.  If you need a primer on sender reputation, check out this article for an overview and definitions.

If you are experiencing delivery issues due to reputation, this means inbox providers and/or blacklist operators have identified your email sending behavior profile as similar to others who send spam to the provider’s network. Each provider uses their own method to develop your reputation profile, and it isn’t something they’ll share with you, however you can build your own model to get an idea of how they view your sending behavior. You’ll need to identify and change areas of your behavior profile that correlate with spam before you can rebuild your reputation.

Identifying Symptoms

Other basic deliverability factors aside, most reputation issues are due to at least one of three major symptoms that correlate with spam: excessive spam complaints, excessive hard bounces, and sending to spam traps.  So what exactly is excessive?

  • Spam complaints rates over 0.1% 
    • Calculated per provider/domain 
    • Even at this rate, there is room for improvement
  • Hard bounces rates over 5% 
    • Calculated per provider/domain
    • High quality senders will strive for <.05% 
  • Sending to any spam traps
    • High quality senders will strive for 0 trap hits
    • Sending to a single high value spam trap can cause a blacklisting
    • Most spam traps are kept secret, treat any trap data you have as limited

Treat the Cause, Not the Symptom

Treating the symptom doesn’t necessarily solve the problem, and what’s worse, you may no longer be able to recognize there is a problem. For example, if you had excessive complaints at, you wouldn’t want to just remove Yahoo users from your list - you would still be hurting your reputation everywhere else, whether you knew it or not. Instead, take a look at these common root cause behaviors and how they correlate with the three major symptoms:

  • Not obtaining explicit permission for marketing
    • The primary cause for unwanted email
    • Includes permission that is implied/unclear
    • Causes pristine spam trap hits, spam complaints, hard bounces
  • Sending to old/unengaged contacts
    • Some email addresses will become invalid
    • Invalid addresses can be revived as recycled spam traps 
    • Recipients may forget they subscribed
    • Causes recycled spam trap hits, spam complaints, hard bounces
  • Collecting invalid addresses or bad data
    • Accidental - Typo’d email address 
    • Intentional - “I don't want to be spammed so im giving you a fake address”
    • Commonly causes typo spam trap hits, but also spam complaints, hard bounces and other spam trap hits
  • Not setting or meeting recipient expectations for content, frequency, or identity
    • Recipients may be put off if you don’t meet their expectations for: 
      • What content you’ll be sending
      • When and how often you’ll be sending
      • Who the email is from (branding, logos, sending address)
    • Causes complaints
  • Sending to recipients that should have been suppressed
    • Occurs if your suppression list is missing or your suppression process isn’t working
    • Most marketing services will automatically suppress complaints, hard bounces and unsubscribes
    • If you change providers, it’s your responsibility to bring your suppression list with you
    • Causes complaints, hard bounces, spam trap hits, and even potential legal action in the case of unsubscribes           

As you can see there is a lot of overlap between root behaviors and symptoms, and in most cases you won’t even be able to measure spam trap hits, so it’s not easy to pick out a single solution. Even though you may not have identified the exact problem, it doesn’t mean there is no reasonable course of action. If you experience any of the three major symptoms, the best approach is to address all of the potential causes by evaluating and improving your marketing practices across the board.  Resolving just one of the above causes will not get you back into the good graces of the inbox providers.  Taking a methodical approach will yield the best results, and the order is important, especially if you’re running any kind of automation as contacts are constantly moving through your marketing pipeline.

Steps to Repair Your Sender Reputation

  1. Perform damage control
    • Temporarily stop sending to the segments that display excessive symptoms, especially if the symptoms are severe. Ideally you should maintain sending consistency, but not if doing so would cause further reputation damage.  
    • Work through the next steps quickly yet thoroughly to help minimize or even avoid any interruption in mail flow.
  2. Find and address problems with lead sources
    • Verify that you obtain explicit permission and set expectations on any web forms or other source of email marketing leads.
    • Check your forms and lead sources for the possibility of intentional/accidental bad input. Does your form incentivize contacts to provide their real email address? Do you use Captcha? Also, consider adding a second email address field for verification. 
    • Implement an email confirmation step into your process for all new leads.  This is most valuable as a way to limit reputation damage - if you somehow get a spam trap on your list, you’ll only send to it once.
  3. Find and address issues with your existing list, content and automation
    • Verify that you have explicit permission for your existing list and remove all contacts that have not provided permission.
    • Perform list hygiene to remove other high-risk contacts from your list such as unengaged, role accounts, and lost or forgotten recipients.
    • Check your campaigns to ensure you are meeting recipient expectations for content, frequency and identity, and you aren’t cross contaminating your segments. This includes checking for objectionable content/subject lines and anything about your email that might cause a valid subscriber to complain, like improperly configured automation.
    • Verify your suppression list is up to date and confirm that any address that complains, hard bounces, or unsubscribes is properly suppressed.
  4. If you’re confident the root cause has been addressed, start repairing your reputation
  • Request delisting from any blacklists.  Most services have a delisting form, such as this one from Spamhaus.  You may need to provide details about what you’ve done to resolve the problem. Remember, you’re dealing with a service that just identified you as an untrustworthy sender (based on past sending behavior) and you’re asking them to trust you again. They have no obligation to do so, so use the utmost respect. Don’t ask to be delisted until you’re sure you’ve resolved the issue, otherwise you’ll be in a worse state than you were before.
  • Start sending again slowly, starting with your highest quality mail (e.g. most engaged contacts). 
  • Don’t rush, as sudden sending spikes can hurt your reputation. Reputation repair can take time, especially if your sender reputation was severely damaged.
  • If you don’t see any excessive complaints, hard bounces, or spam trap hits, continue slowly ramping up until you reach your full volume.  

If you continue to see symptoms, go back to step one and start again. This process is essentially an exercise in self behavior modification in which objectivity is critical. Your goal is to not only resolve the symptoms, but to change the core behavior profile that caused the reputation issue in the first place.

  • Try to remove any assumptions you made about your list quality, lead generation methods, and sending practices (Do you really have permission?). 
  • Verify you have committed to industry standard best practices across the board, and avoid making exceptions to these practices because of your industry or other circumstances. While the logic may make sense to you, it doesn’t matter to those that measure your reputation: the recipient inbox providers.
  • The goal is to ensure every email that you send is both wanted and expected by your recipients, so be honest with yourself as you perform your evaluation.

Prevention is the Best Medicine

Sender reputation issues can be costly to your business - reallocating resources to handle the repair, losing email contact with customers and interested leads - these unplanned effects can impact your bottom line, especially if your revenue stream is dependent on email marketing. After spending time to repair your reputation, it’s worthwhile to invest a little more time to protect your reputation going forward and prevent these kinds of issues from occurring again. Implement industry standard best practices into your marketing process in a permanent manner, and make sure anyone who handles your marketing operations is aware of how to manage your sender reputation and how it impacts your business. It won’t just help you maintain trust with recipient inbox providers or get your email into the inbox, it’s also smart business.