How to Fix Cloudflare ERR_SSL_VERSION_OR_CIPHER_MISMATCH on Chrome (And Other Browsers)

Website uses an unsupported protocol.

ERR_SSL_VERSION_OR_CIPHER_MISMATCH.

It’s frustrating to see this error, especially on your own website.

The ERR_SSL_VERSION_OR_CIPHER_MISMATCH error can appear even if you use the latest Chrome on a current Windows or Mac system. Older setups are more prone to it, but newer ones can have the same problem.

Your browser is reporting a problem with the TLS Handshake, the process it uses to check that it is connecting to the right website. A misconfiguration or unsupported version can cause this problem.

You might also see either of these messages:

• The client and server don’t support a common SSL protocol version or cipher suite
• Error 113 (net::err_ssl_version_or_cipher_mismatch): unknown error

The checks below can help you find and fix the cause.

Check Your Browser And Operating System

Start by checking whether your browser or operating system is out of date. If that is the cause, the other fixes below will not resolve it.

An old browser can cause the ERR_SSL_VERSION_OR_CIPHER_MISMATCH error. Internet Explorer 6 is one example.

An older operating system can also cause the error as it loses support for newer technologies, such as TLS 1.3, and browsers stop supporting it.

Google Chrome, for example, ended support for Windows XP in 2015.

If you are unsure whether your browser or system is current, open the website on another device. A smartphone with its updates installed is a useful comparison.

If the website loads on the newer device, your browser or operating system is likely to be the cause.

Download the latest Chrome version if you have not done so, then check whether the error has gone.

If the error remains, your operating system might be responsible. Try the latest version of Windows, Mac, Ubuntu or whichever system you use.

These checks apply when the error appears on your computer but not on a newer device. If the site works on your smartphone and your computer’s browser and operating system are already current, your antivirus software could be responsible.

Temporary Disable Antivirus

Antivirus software can insert its own certificates between your browser and the internet. This can cause the ERR_SSL_VERSION_OR_CIPHER_MISMATCH error.

Temporarily pause or disable your antivirus software, then check whether the error still appears.

If the error remains, check whether the SSL certificate is set up correctly.

Verify Your SSL Certificate is Correct

After ruling out problems on your device, check that the website’s SSL certificate is valid.

You can check the certificate with a free SSL tool, such as this one from SSL Labs.

Enter your domain in the Hostname field, then click “Submit”, as shown below:

The scan checks your site’s SSL/TLS configuration and shows whether the certificate is valid. This takes a few minutes.

If the certificate is invalid, check the possible causes below.

Check for Certificate Name Mismatch

A name mismatch on the certificate can cause an ERR_SSL_VERSION_OR_CIPHER_MISMATCH error.

The SSL Labs test below shows how to identify a name mismatch. SSL Labs lists these possible explanations:

• 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.

Chrome DevTools can also show certificate mismatches. However, the ERR_SSL_VERSION_OR_CIPHER_MISMATCH error often prevents you from checking the certificate there.

To check the certificate in Chrome DevTools:

1. Open the website in Google Chrome
2. Right-click the website and choose “Inspect.”
3. Select the Security tab, then click “View certificate.”
4. Find the issued domain in the certificate information. A name that does not match the website you are visiting points to a certificate mismatch.

Wildcard certificates and other variations are possible. For a typical site, the name should match exactly.

The Mac example below looks slightly different from the Windows version:

If the certificate name matches, an old TLS version could be the cause.

Check for an Old TLS version

Running an old TLS version can cause the ERR_SSL_VERSION_OR_CIPHER_MISMATCH error.

Your web server should run at least TLS 1.2, preferably TLS 1.3. Cloudflare enables TLS 1.3 by default.

Check the SSL Labs results to see whether your server uses an old TLS version.

The configuration section shows the TLS version used by the server with that certificate.

If the TLS version is old, contact your host and ask them to update it.

Clearing your computer’s SSL state is another possible fix.

Clear the SSL State On Your Computer

You can also try clearing Chrome’s SSL state.

On Windows, clear the SSL state in Chrome with these steps:

• Click the Google Chrome Settings icon, then click Settings.
• Select “Show advanced settings”.
• In Network, select Change proxy settings to open the Internet Properties dialog box.
• Select the Content tab.
• Select “Clear SSL state”, then click the OK button.
• Close Chrome and reopen it to restart the browser

The Mac process is a little more involved. Follow this guide to delete an SSL certificate on a Mac.

The final possible cause is a cipher mismatch, as named in ERR_SSL_VERSION_OR_CIPHER_MISMATCH.

Check RC4 Cipher Suite

The RC4 cipher suite was removed in Chrome version 48.

An RC4 cipher mismatch rarely causes this error, though it is possible.

Microsoft recommends that RC4 be disabled. If you manage this server, consider configuring a different cipher suite.

The SSL Labs report shows the server’s current cipher suite.