Solved: Err_Ssl_Version_or_Cipher_Mismatch Firefox Error? [6 Methods]

SSL errors are common issues encountered by internet users. One of the most frequent problems is the ERR_SSL_VERSION_OR_CIPHER_MISMATCH Firefox error.

Although some of the error messages may be common, this message is usually unknown to most users. It can be daunting when you are in the middle of some talk daunting but do not worry. This error may be unknown, but it is easy to resolve. The system shows this error when the browser classifies a problem with the SSL certificate version of the website.

What is Err_Ssl_Version_or_Cipher_Mismatch Firefox Error?

When a user tries to connect to a website, the browsers check the SSL certificate of the website automatically. This happens every time whenever a connection to the website is maintained. It is a correspondence that the requested website is genuine. 

It also indicates that the website has implemented the protocol to protect the connection. In technical terms, we call this process a TLS handshake. It refers to the protocol which ensures safe communication between the web server and a user’s system. 

In any case, if the user’s browser or the web server is unable to sustain an rc4 cipher suite or standard SSL protocol version during the TLS handshake, then the browser will show the error message ERR_SSL_VERSION_OR_CIPHER MISMATCH Error

Causes for Err_Ssl_Version_or_Cipher_Mismatch Firefox Error

The ERR_SSL_VERSION_OR_CIPHER MISMATCH error is the browser’s method of safeguarding the user from landing on any unsafe websites. A website may use an unsupported version of a particular protocol with security flaws. It can be a source of serious threat to your device. It can also lead to the floating of wrong information on the website.

There can be several issues leading to the failed attempt to maintain a standvard SSL protocol between the browser and web server and leading to ERR_SSL_VERSION_OR_CIPHER MISMATCH Error:

1. Old TLS versions 

the web server may be using an outdated version of TLS and hence no longer supported by the web browsers. 

2. Invalid SSL certificates

The SSL certificate for the domain may be assigned to a different domain name, thus triggering the mismatch error.

3. Outdated operating systems or browsers

The outdated operating systems or browsers may lead to mismatch errors, as a TLS handshake is not attempted in this case. 

4. The browser’s cache 

The cached data may not imitate the security updates for the website.

5. QUIC protocol

It is a Google project serving as the alternative common security solution, but it leads to the error.

6. Antivirus program

A misconfigured antivirus program can trigger a false alarm leading to the error. Notably, this error usually occurs on websites that imply SSL certification and HTTPS encryption for safe entry and information exchange.

So, keep an eye on the lock icon on the Websites which symbolize this encryption.

Fixing the  ERR_SSL_VERSION_OR_CIPHER_MISMATCH Error [6 Easy Methods]

You can fix the ERR_SSL_VERSION OR CIPHER MISMATCH, such as Typing in google chrome flags in the address bar error, by following simple steps.

1. Disabling the QUIC (Quick UDP Internet Connection) Protocol

The QUIC protocol is an experimental project introduced by Google aimed at improving the connection of web applications by applying the User Datagram Protocol (UDP). 

However, this protocol often appears as the source of error warnings, including the ERR_SSL_VERSION_OR_CIPHER_MISMATCH Firefox error message

One way to fix the ERR_SSL_VERSION OR CIPHER MISMATCH error is to disable it by following the steps:

  • Open firefox 
  • Search QUIC
  • Look for the Experimental QUIC Protocol
  • A drop-down menu will appear that select Disable

2. Checking the SSL/TLS Certificate

Going through this certificate is the best way to fix the err_ssl or certificate name mismatch error. If this shows that the certificate name is mismatched, outdated, or invalid, it can cause the error. 


There are online tools, Qualys SSL Labs, to check this SSL certificate. It grades a particular SSL connection and detects any certificate name mismatch. 

3. Disable Your Antivirus or Firewall

Security issue arises when the firewall or antivirus is Improperly configured. ERR_SSL_VERSION_OR_CHIPER_MISMATCH problem can also occur. Poor configuration results in false alarms, falsely claiming that a website is unsafe. This poor configuration indicates safe websites as dangerous ones. 

To check this possibility, temporarily restrict your antivirus software to evade serious security issues.

If the antivirus pertains to automatic SSL scanning, disable this feature to eliminate the error message. This way, you will not need to deactivate the entire antivirus software.

4. Clearing the Web History or Cache

The web history and cache store data comprise the websites last visited. The cache data comprises images, text, or files assisting the browser in loading the website quicker and more promptly on the next visit. But storing old cache can be troublesome, particularly when the sites you visit have updated versions available. 


Hence when cache data is not deleted for a more extended period, it can lead to severe security risks and SSL errors. Clear the cache, and restarting the browser can quickly resolve the SSL errors. 

5. Enable TLS 1.3 Support

TLS is a source of secure connection. This protective layer is the direct beneficiary of the SSL technology. Most website browsers like Firefox are already supported by TLS 1.3. in case of an older version of TLS, carry out these steps to allow the browser to older version of TLS support:

  • Open the Firefox browser
  • Type google chrome flags in the address bar: chrome://flags 
  • Hit Enter
  • In the search field, Search for TLS 
  • Enable TLS 1.3 support from this option

6. Configuring SSL over the Cloudflare

A misconfiguration between the SSL settings and Cloudflare can lead to the ERR_SSL_VERSION_OR_CIPHER MISMATCH error. In this case, you will need the test result issued by the SSL Labs. If the results state that the SSL certificate is unacceptable, then misconfiguration is the cause of the error. The solution is to reconfigure this mismatch. 

There can be two ways to reconfigure the SSL. These methods vary with the SSL types, so you do it either through the Cloudflare dashboard or the hPanel. Once this configuration is corrected, you will not encounter the error. 


We suggest you not be alarmed if you meet any unidentified error message, especially the ERR_SSL_VERSION_OR_CIPHER MISMATCH Error. Go through the message carefully and find the proper fix for the issue. If the corresponding fix is not applied, there are high chances of the reoccurrence of the error. 

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