How to recover from a bad sender reputation
Written by
Kanika Sreen
Kanika Sreen

Subscribe for updates

How to recover from a bad sender reputation

Published : May 10, 2022 | Updated : April 25, 2024

Sender reputation is indispensable to successful email marketing

“A person’s credit report is one of the most important tools consumers can use to maintain their financial security and credit rating, but for so long many did not know how to obtain one, or what to do with the information it provided.”- Rubén Hinojosa.

A sender reputation score is not that different from a credit report; restoring it from a low point can be a real challenge. Rising spam complaints, low CTRs, thwarted inboxing, etc., show up long before your reputation takes a hit. Stay alert – these are the things that matter for deliverability.

How do ISPs define sender reputation?

ISPs rate email senders on spam complaints, content quality, sending frequency, message size, user engagement, etc. On a scale of 0-100, a 70+ score is sure to get you good inboxing. Let’s look at some factors that influence sender reputation the most.

IP reputation

IP reputation indicates the quality of an IP address. ISPs monitor bounce rates, spam complaints, volume, frequency of emails, etc., to determine the final score for an IP address.

  • Shared IP

A shared IP means that multiple senders use a common IP address to send emails. The collective action of all users determines the final outcome. If others use bad sending practices, the IP gets a bad reputation, and your reputation takes a nosedive too.

  • Dedicated IP

A dedicated IP is used by a single sender who is solely responsible for creating and maintaining the reputation. The cost associated is definitely higher than that of a shared IP, but the risk reduction makes it worth the price.

Domain reputation

Domain reputation is directly connected to your brand name and is more permanent in nature than an IP address. You cannot change it like an IP address to fix a bad reputation. To fix domain reputation, pay attention to the undermentioned factors:

  • Blacklisting

Excessive spam complaints lead to the blacklisting of a domain. A blacklisted domain has a bad reputation and poor email deliverability. Emails from such domains are either rejected or placed directly in spam.

  • Domain age

ISPs are watchful of domains younger than a month. New domains are at higher risk of getting blacklisted. It takes up to 12 weeks to gradually warm up a domain.

  • Email sending practices

ISPs analyze the frequency, volume, consistency, content, relevance, etc., of emails sent by a domain. Domains with emails failing on these criteria end up on blacklists.

  • Spam traps

Spam traps are fake email ids created by ISPs to identify senders following bad sending practices. Emails landing in spam traps can lead to immediate blacklisting of domains.

What can marketers do to recover from a bad reputation?

Recovering from a bad reputation is a journey, including everything from cleaning up sending practices to monitoring the flow of emails. Understand the roadmap with the undermentioned guidelines:

Calculate the current reputation score with reliable tools

A reputation score can help you assess your current email program and its potential risks. Some good tools to check the reputation scores are:

  • BarracudaCentral

BarracudaCentral maintains a real-time record of both good and bad senders. It keeps a check on the internet to identify advanced spam methods.

  • Sender Score

SenderScore determines the credibility of a sender. It rates you from 0 to 100, wherein a higher number means a better reputation.

  • TrustedSource

TrustedSource is a service provided by McAfee. It includes reputation scores for URL, IP address, domain, etc.

Incorporate strategies that support a healthy reputation score

Following email marketing best practices is one way to maintain a good sender reputation. Some elements that deserve special attention are:

  • Maintain a good SPF and DKIM record

SPF* specifies the IP addresses that are authorized to send emails on a sender’s behalf. DKIM* is a digital signature secured with encryption to validate a domain’s identity. It indicates that messages have not been modified during transit. Together, these authentication methods work to identify the credibility of sending IP addresses and domains. SPF failure indicates spoofing and leads to emails not getting delivered at all. DKIM failure leads to emails getting into spam or facing rejection by the server. Thus, these must be carefully published in the DNS.

  • Follow a strict DMARC regime

DMARC* is an authentication policy and protocol formulated on top of SPF and DKIM. It specifies action when an email fails authentication. 

It involves: 

  1. matching SPF and DKIM records of an email
  2. taking specified action when authentication records fail, and
  3. reporting domains from where such emails originate. A strict DMARC policy is required not only to prevent spoofing and phishing attempts but also to secure email deliverability.
  • Ensure IP and Domain warming

IP and Domain addresses that are new or have not been in use require a warm-up process. To build an identity with ISPs, gradually increase the email volumes over 8-12 weeks. Pay special attention to email cadence, content, and mailing list when drafting emails for warmup.

  • Practice email list hygiene

Email list hygiene or email scrubbing is the process of removing inactive contacts from mailing lists. Having active subscribers on the list lowers bounce rates and increases deliverability. This practice should be followed in a routine.

  • Use double opt-ins, don’t buy email lists

Double opt-ins are a smart way to secure the consent of recipients to receive your emails. Purchased email lists can expose you to spam traps, or worse, getting blacklisted by ISPs. Always use double opt-in methods to build mailing lists.

Monitor your reputation

When all is done to clean up your reputation, remember to track and maintain it. A comprehensive tool like grademyemail evaluates reputation and provides actionable insights to address key issues with it. It works on Netcore Cloud’s proprietary AI-based algorithms. These examine your emails against 100+ email metrics and identify issues with your current email configuration. The tool also checks records for SPF, DKIM, DMARC, and BIMI. 


It is tough to create a good sender reputation and tougher to maintain it while sending

marketing emails at scale. Understanding and following the above best practices result in consistent inbox placement, high user engagement, and improved KPIs.

Netcore Cloud’s AI-powered email platform can uplift your email program and boost your ROI. Our email wizards can help you assess, analyze, strategize, and achieve email marketing goals. Connect with us to understand how you can benefit from our expertise and experience – we send over 17 billion emails a month for businesses across 18 countries.

*SPF: Sender Policy Framework

*DKIM: DomainKeys Identified Mail

*DMARC: Domain-based Message Authentication Reporting and Conformance

Unlock unmatched customer experiences,
get started now
Let us show you what's possible with Netcore.
Written By: Kanika Sreen
Kanika Sreen
Assistant Manager - Content Strategist