---
title: "Invalid DKIM signature error: Here’s how you can fix it | AutoSPF"
description: "To thrive in today’s digital world laden with cybersecurity threats, you must implement certain measures to tighten your security."
image: "https://autospf.com/og/blog/invalid-dkim-signature-error-heres-how-you-can-fix-it.png"
canonical: "https://autospf.com/blog/invalid-dkim-signature-error-heres-how-you-can-fix-it/"
---

Quick Answer

To thrive in today’s digital world laden with cybersecurity threats, you must implement certain measures to tighten your security. One way is to guard your email ecosystem with authentication protocols that ensure authorized emails are sent from your domain. Now, when you set up email authentication protocols like SPF, DKIM, and DMARC, you should be very careful because even a.

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![Invalid DKIM signature error](https://media.mailhop.org/autospf/images/2024/10/spf-record-checker-3894.jpg) 

To thrive in today’s digital world laden with [cybersecurity](/10-reasons-for-regular-spf-record-checks-in-cybersecurity/) threats, you must implement certain measures to tighten your security. One way is to guard your [email ecosystem](https://www.axigen.com/articles/email-ecosystem%5F128.html) with authentication protocols that ensure authorized emails are sent from your domain. Now, when you set up email authentication protocols like [SPF](/blog/what-is-spf-email-a-guide-to-sender-validation-technology/), DKIM, and [DMARC](/10-reasons-for-regular-spf-record-checks-in-cybersecurity/dmarc-record-check/), you should be very careful because even a tiny error can lead to big problems. One such issue is the invalid DKIM signature, which can wreak havoc on your entire [email security](/) strategy. 

_DKIM ([RFC 6376](https://datatracker.ietf.org/doc/html/rfc6376)) signs email messages cryptographically, and unlike SPF, the signature survives email forwarding - which is why DMARC alignment via DKIM is more reliable than SPF alignment for forwarded mail and mailing lists._

Learn more in our [comprehensive DKIM guide](/blog/what-is-dkim-email-authentication-guide/).

If you do not want your emails to be tampered with and ruin your [brand reputation](https://sendpulse.com/support/glossary/brand-reputation), you should fix this error! Not sure how to go about it? This article is your ultimate guide to resolving this issue so that your emails will be delivered to recipients securely and efficiently.

## What Is DKIM signatures?

DKIM, or DomainKeys Identified Mail, is an [email authentication](/spf-too-many-dns-lookups/spf-lookup/) protocol that assures an email has not been tampered with on the way to its recipient’s inbox. It uses two keys to do this - a public and a private key. Your server uses a [private key](https://www.coinbase.com/learn/crypto-basics/what-is-a-private-key) to create a unique [digital signature](https://www.techtarget.com/searchsecurity/definition/digital-signature) that will be added to the email header. _As for the public key, it is published in the DNS record for the recipient’s server to verify the authenticity of the sent message_. 

Unlike a typical email signature that you find at the bottom of the email, a DKIM signature is added to the [email header](https://proton.me/blog/what-are-email-headers) itself and isn’t visible to users. Yet it assures your recipients that the emails they are receiving haven’t been manipulated or altered in anyway by a [cyberattacker](https://www.infosecurity-magazine.com/news/cyber-attack-exposes-credit-card/) trying to gain unauthorized access to their system. _So, if this DKIM signature isn’t properly configured or is invalid, it can lead to a lot of security risks and email deliverability issues_. 

For instance, if the DKIM signature does not match the public key in your [DNS record](https://www.techopedia.com/definition/5349/dns-record), then it becomes impossible for the recipient’s server to verify the authenticity of the email. Moreover, in such cases, when the [spam filters](https://www.aljazeera.com/economy/2022/10/24/republican-committee-in-us-sues-google-over-email-spam-filters) cannot verify your emails as authentic, they might as well flag your emails as suspicious or even reject them outrightly.

![spam filters](https://media.mailhop.org/autospf/images/2024/10/spf-flattening-1.jpg) 

## Signs of an invalid DKIM signature 

We have learned that an invalid email can significantly impact your [email deliverability](/blog/how-does-spf-help-marketers-in-improving-email-deliverability/) and security, but without a complete understanding of how to fix this problem, this information isn’t good enough. To resolve this issue, you first need to know what’s wrong with your DKIM signature. Only then can you take the necessary steps to correct it. Here are some signs that indicate your DKIM signature may be invalid:

- If the domain in your DKIM signature does not match the domain from which the email came, the receiving server will view it as suspicious and might even [mark it as spam](https://pressgazette.co.uk/publishers/digital-journalism/facebook-spam-posts-independent-small-news-publishers/) or block it altogether.
- The key published in the DNS is what the recipient’s server uses to authenticate your DKIM signature. _If it’s not published right or there’s a mistake, their server will either mark your email as untrustworthy or reject it_.
- If your DKIM key is shorter than 1024 bits, be prepared for your emails to be intercepted by [threat actors](https://thehackernews.com/2024/07/tag-100-new-threat-actor-uses-open.html). Email providers will flag any key of less than [2048 bits](https://sendgrid.com/en-us/blog/2048-bit-dkim-keys), primarily because emails with shorter [DKIM keys](/blog/when-should-you-rotate-your-dkim-keys/) are not secure enough.
- In case your email is modified during an auto-forwarding, the DKIM signature is bound to be broken. _This broken DKIM signature is a telltale sign for the receiving server that your email has been tampered with, which then treats it as a threat, therefore affecting deliverability_.
![DNS settings](https://media.mailhop.org/autospf/images/2024/10/spf-record-syntax-7618.jpg) 

## How Do You Fix an invalid DKIM signature?

Now that you know what are the potential reasons your [DKIM signature](https://docs.mapp.com/docs/dkim-signature) could be broken or invalid, it’s time to learn how to fix it. 

- The first step is to run the DKIM record through a checker or validator to detect any mistakes. The checker or validator will let you know whether the record is correctly published, whether there are any syntax problems, or whether the [public key](https://www.investopedia.com/terms/p/public-key.asp) is available.
- If the validator comes across any such issues, you’ll need to go into your [DNS settings](https://www.ntchosting.com/encyclopedia/dns/settings/) to correct them. While doing so, make sure that you enter the correct values and address all the pain points that were flagged by the tool.
- Once done, all you have to do is save the changes and wait for some time for them to reflect.

We understand that configuring [DKIM](/10-reasons-for-regular-spf-record-checks-in-cybersecurity/dkim-record-check/) can be tricky, especially when there are so many complexities involved. The good news, though, is that it’s not rocket science either. _Moreover, the ‘invalid DKIM signature’ error is more common than you think_. But with the right tools and a bit of attention to detail, you can rest assured that your DKIM configuration is on point and your emails are secure.

## Topics

[ DKIM ](/tags/dkim/)[ DKIM record ](/tags/dkim-record/)[ DMARC ](/tags/dmarc/)[ email security ](/tags/email-security/)[ SPF ](/tags/spf/) 

![Brad Slavin](https://media.mailhop.org/autospf/images/authors/brad-slavin.jpg) 

[ Brad Slavin ](/authors/brad-slavin/) 

General Manager

Founder and General Manager of DuoCircle. Product strategy and commercial lead for AutoSPF's 2,000+ customer base.

[LinkedIn Profile →](https://www.linkedin.com/in/bradslavin) 

## Ready to get started?

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[ Book a Demo ](/book-a-demo/) 

## Related Articles

[  Intermediate 6m  How To Configure Sendgrid DKIM Alongside DMARC And SPF Records?  Apr 24, 2026 ](/blog/how-to-configure-sendgrid-dkim-alongside-dmarc-and-spf-records/)[  Intermediate 4m  Setting SPF, DKIM, and DMARC for Loops.so  Oct 28, 2025 ](/blog/setting-spf-dkim-and-dmarc-for-loops-so/)[  Intermediate 5m  Setting up SPF and DKIM records in GoDaddy  Aug 22, 2025 ](/blog/setting-up-spf-and-dkim-records-in-godaddy/)[  Intermediate 15m  SPF Sendgrid Configuration Guide: Ensure Your Emails Pass Authentication  Nov 7, 2025 ](/blog/spf-sendgrid-configuration-guide-ensure-your-emails-pass-authentication/)

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