What does it mean if an IP address has a SenderScore of 10?
Matthew Whittaker
Co-founder & CTO, Suped
Published 6 May 2025
Updated 18 Aug 2025
6 min read
What does a SenderScore of 10 mean for an IP address? In short, it is a critical warning signal for your email program. SenderScore, provided by Validity, is a key metric that assesses the reputation of an IP address on a scale of 0 to 100, indicating how trustworthy mailbox providers view your email sending activities. A score of 10 places your IP address in the lowest percentile, suggesting severe issues that are likely causing significant email deliverability problems.
A low SenderScore, particularly one as low as 10, means that internet service providers (ISPs) and mailbox providers view your sending IP address with extreme suspicion. This score is calculated based on a rolling 30-day average of various sending metrics, including complaint rates, spam trap hits, unknown user rates, and volume consistency. When your score is this low, it strongly indicates that your emails are either not reaching the inbox at all or are being heavily filtered into spam or junk folders.
I've seen many instances where such a low score results in direct rejections, with bounce messages explicitly stating the SenderScore is too low. This isn't just a minor hurdle, it's a major roadblock that prevents your legitimate emails from reaching their intended recipients, regardless of how valuable your content might be.
The dire implications of a SenderScore of 10
A SenderScore of 10 translates directly into poor email deliverability. Mailbox providers use this (and similar) scores to decide whether to accept, delay, or reject emails originating from your IP address. At such a low score, most providers will be highly suspicious of your mail, leading to a significant drop in your inbox placement rates.
This low score means your IP address is almost certainly on multiple public and private blocklists (or blacklists). Being listed on a blocklist indicates that your IP has been identified as a source of unsolicited or problematic email, further harming your reputation. Even if your emails aren't outright rejected, they are highly likely to land in the spam folder, making them invisible to your recipients.
A SenderScore of 10 is often associated with extremely high complaint rates, a large number of unknown users (bad email addresses), and frequent encounters with spam traps. These factors erode trust with mailbox providers and can lead to your emails being quarantined or outright rejected. This makes it challenging to engage with your audience and can severely impact your communication efforts.
Ultimately, a SenderScore of 10 signals that your email sending infrastructure or practices are severely misaligned with industry best practices, making it nearly impossible for your messages to achieve successful delivery to inboxes.
Why your IP address might have such a low score
There are several common reasons why an IP address might plummet to a SenderScore of 10. Understanding the root cause is crucial for effective remediation. Often, such a low score is a symptom of severe underlying issues with your email sending practices.
The most common culprits for a SenderScore of 10 include:
High complaint rates: If a large percentage of your recipients are marking your emails as spam, it signals to mailbox providers that your content is unwanted or unsolicited.
Spam trap hits: Sending to email addresses that are actually spam traps (addresses designed to catch spammers) will severely damage your reputation. This indicates poor list hygiene. Read more about how spam traps work.
High bounce rates: A high number of hard bounces, particularly from unknown users, suggests that your mailing list contains many invalid or stale addresses.
Sending volume spikes: Sudden, large increases in sending volume from a previously low-volume IP address can trigger spam filters, especially if the IP is not properly warmed up.
Shared IP pool issues: If you are sending from a shared IP address, the sending practices of other users on that same IP can negatively impact your SenderScore.
Even if your own email sending practices are generally good, being on a shared IP address means your reputation can be affected by the poor behavior of other senders sharing that same IP. This often leads to frustration as you might be doing everything right, yet your SenderScore remains low due to factors outside your direct control.
Sometimes, a low SenderScore can be attributed to a new IP address that hasn't undergone proper IP warming. IP warming involves gradually increasing email volume over time to build a positive sending history. Without this process, sending high volumes from a new or cold IP can immediately trigger spam filters and result in a very low score.
Example of a suspicious email header due to low reputationplaintext
X-Spam-Status: Yes, score=15.0 required=5.0
tests=RCVD_IN_BL_LOW,RCVD_IN_XBL,URIBL_BLOCKED
autolearn=no autolearn_force=no
version=3.4.0
X-Spam-Report:
* 3.0 RCVD_IN_BL_LOW RBL: Listed on low-reputation blacklist
* 5.0 RCVD_IN_XBL RBL: Listed on XBL (e.g. Exploits, Trojans)
* 7.0 URIBL_BLOCKED ADMINISTRATOR NOTICE: The query to URIBL was blocked.
* See http://uribl.com/ref.shtml for more information.
X-Mailer: SomeMailSender (possibly compromised)
Steps to recover from a low SenderScore
Recovering from a SenderScore of 10 requires a systematic and diligent approach to rebuilding your email sending reputation. This isn't a quick fix, but a sustained effort focusing on best practices. You can delve into more detail on why your score has dropped and what to do about it in our comprehensive article.
The immediate priority should be to identify and address the underlying issues causing the low score. This involves a thorough audit of your email lists, sending practices, and authentication protocols. For example, ensuring proper email authentication like SPF, DKIM, and DMARC is fundamental for proving your legitimacy to mailbox providers. Learn more about these in a simple guide to DMARC, SPF, and DKIM.
Identifying the problem
Check email authentication: Verify that your SPF, DKIM, and DMARC records are correctly configured. Misconfigurations can lead to emails being marked as suspicious, even if legitimate.
Analyze bounce logs: Look for high rates of hard bounces (unknown users) or soft bounces (temporary issues) that could indicate an unhealthy mailing list.
Review spam complaint data: If possible, check feedback loops with major ISPs to see who is complaining and why. This can reveal issues with content or audience targeting.
Assess shared IP impact: If on a shared IP, determine if other senders are causing issues. This might necessitate a move to a dedicated IP.
Implementing solutions
Clean your email lists: Remove invalid, inactive, and problematic email addresses, including any known spam traps. Regularly verify your lists to maintain hygiene.
Implement opt-in practices: Ensure all subscribers explicitly consent to receive your emails. Double opt-in is highly recommended to prevent spam complaints.
Improve email content: Avoid spammy keywords, excessive links, or poorly formatted content that could trigger filters. Provide clear unsubscribe options.
Warm up new IPs: If using a new IP, follow a strict IP warming schedule to gradually build reputation. This helps ISPs trust your sending volume. You can find more information about this in how to warm up your IP address.
Monitor blocklists: Regularly check if your IP is listed on any major blocklists and take steps to request delisting if you've resolved the underlying issues. Our blocklist checker can help you with this.
Remember, consistent, good sending behavior over time is what truly builds and sustains a healthy SenderScore. There is no instant fix for a score of 10, it requires dedication to best practices and continuous monitoring.
Views from the trenches
Best practices
Maintain extremely clean email lists by regularly removing inactive or unengaged subscribers to reduce bounce and complaint rates.
Always implement double opt-in for new subscribers to ensure explicit consent and reduce spam complaints.
Continuously monitor your sender reputation metrics, including SenderScore and other reputation services, to detect issues early.
Ensure all your email authentication protocols (SPF, DKIM, DMARC) are correctly configured and aligned.
Segment your email lists and tailor content to specific audiences to increase engagement and reduce spam complaints.
Common pitfalls
Purchasing or using old, unverified email lists, which often contain spam traps or invalid addresses.
Sending to unengaged subscribers, leading to high complaint rates and low open rates.
Ignoring email bounce messages, which provide critical information about deliverability issues.
Failing to implement or properly configure email authentication standards, making your emails appear untrustworthy.
Sending sudden, large volumes of email from a new or cold IP address without proper warming.
Expert tips
An IP address with a SenderScore of 10 signals very severe deliverability problems.
High complaint rates and spam trap hits are major contributors to extremely low SenderScores.
Shared IP addresses can be particularly vulnerable to other senders' poor practices affecting your score.
Recovering from a SenderScore of 10 involves diligent list hygiene, proper authentication, and consistent, good sending behavior.
IP warming is crucial for new sending IPs to establish a positive reputation from the start.
Expert view
Expert from Email Geeks says a SenderScore of 10 is very low and indicates serious deliverability issues.
January 17, 2024 - Email Geeks
Marketer view
Marketer from Email Geeks says they recently encountered a bounce message explicitly referencing a low SenderScore.
January 17, 2024 - Email Geeks
Moving forward: maintaining a healthy sender reputation
A SenderScore of 10 is a clear indicator that your email deliverability is in serious jeopardy. It means that most mailbox providers view your IP address with high suspicion, often leading to emails landing in spam folders or being outright rejected. Addressing this requires a comprehensive strategy focused on rectifying past issues and committing to ongoing best practices.
By diligently cleaning your lists, implementing robust authentication, warming up IPs correctly, and continuously monitoring your reputation, you can gradually improve your SenderScore. This proactive approach will not only help you recover from a low score but also ensure your emails consistently reach the inbox, fostering better engagement and communication with your audience.
spam traps work.
blocklist checker can help you with this.
