Learn ways to kick the ‘ERR_SSL_VERSION_OR_CIPHER_MISMATCH’ Error to the curb in a few quick steps

Are website visitors facing the ERR_SSL_VERSION_OR_CIPHER_MISMATCH error on your website? Of course they are; why else would you be here, reading this article? This error is pretty common, and thousands of users around the world face it every single day.

We too faced the same error, but fortunately, we’re lucky to have SSL experts that have spent years solving these errors. This was just another error and needless to say, we’ve come up with accurate solutions.

The ERR_SSL_VERSION_OR_CIPHER_MISMATCH error often stems from the depreciation of the RC4 cipher. (The RC4 cipher was deemed insecure almost a decade ago, and Chrome doesn’t want you or your users to be in danger.) However, this isn’t the only causes

Examples of This Error on Different Platforms

  • Chrome: ERR_SSL_VERSION_OR_CIPHER_MISMATCH (formerly SSL_OBSOLETE_VERSION)
  • Firefox: Error code: SSL_ERROR_NO_CYPHER_OVERLAP
  • OpenSSL: X509_V_ERR_SIGNATURE_ALGORITHM_MISMATCH

Here’s a quick peek at what this error looks like in the wild:

A screenshot of the ERR_SSL_VERSION_OR_CIPHER_MISMATCH error in Firefox
Image caption: A screenshot of the error “ERR_SSL_VERSION_OR_CIPHER_MISMATCH” in Firefox.

What Causes the ‘ERR_SSL_VERSION_OR_CIPHER_MISMATCH

There can be three main reasons behind this error:

  1. Your server is using an obsolete TLS version (i.e., TLS 1.0 or 1.1).
  2. Your website doesn’t use SSL (or uses a content delivery network [CDN] that doesn’t support it)
  3. Your server still supports the deprecated RC4 cipher.

Alright. Now that we know what the error is and what its common causes are, let’s get straight to solving ERR_SSL_VERSION_OR_CIPHER_MISMATCH error.

How to Fix ERR_SSL_VERSION_OR_CIPHER_MISMATCH Error

Step 1: Go to SSL Labs

Test your server using Qualys’ free SSL check tool. This will help you identify the root cause of your error and fix the problem accordingly.

Step 2: Check Your SSL Certificate

  • Go to Test your server
  • Enter your hostname. For example, yourdomainname.com
  • Click Submit

Step 3: Is Your SSL Certificate Name Mismatched?

Often, certificate name mismatching could be causing ERR_SSL_VERSION_OR_CIPHER_MISMATCH error. As SSL Labs will show you, there are numerous reasons behind certificate name mismatch. Here are possible reasons:

  • The site does not use SSL but shares an IP address with some other site that does.
  • The site no longer exists, yet the domain still points to the old IP address, where some other site is now hosted.
  • The site uses a content delivery network (CDN) that doesn’t support SSL.
  • The domain name alias is for a website whose name is different, but the alias was not included in the certificate.

Check for each and try to fix it.

Step 4: Are you running older SSL/TLS versions?

If you’re running an older version of SSL/TLS, it could be causing ERR_SSL_VERSION_OR_CIPHER_MISMATCH error. When you run your server check-in using the free SSL Labs tool, you’d find SSL/TLS versions under the configuration section. See whether any old, insecure protocols (i.e., SSL 2, SSL 3, TLS 1.0 and/or TLS 1.1) are still being supported.

If so, disable it on your server ASAP.

Step 5: Does your server support the RC4 cipher?

The main reason why your Chrome throws up ERR_SSL_VERSION_OR_CIPHER_MISMATCH error is that of the RC4 cipher. Deprecated a long time ago, the RC4 cipher was deemed insecure. When you run the scan in SSL labs, go to the Cipher Suites section to check RC4 cipher. If your server supports it, disable it ASAP!

If you can’t turn it off, enable other ciphers.

We hope one of these solutions has helped you get rid of the ERR_SSL_VERSION_OR_CIPHER_MISMATCH error.

Editor’s Note: This article was originally published in July 2018. It’s been updated as of March 31, 2025 with newer, more current information.

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Welcome to Savvy Security, a blog focused on providing practical cybersecurity advice for website owners and small businesses. Our team brings you the latest news, best practices and tips you can use to protect your business...without a multi-million dollar budget or 24/7 security teams.