• October 1, 2022

SSL_ERROR_NO_CYPHER_OVERLAP in Mozila Firefox browser

Many users have chosen Firefox as their main Internet browser. This is understandable, the browser is quite stable, has a nice interface, works quickly and allows you to expand its functionality on an almost unlimited scale. Nevertheless, we cannot say that there are no failures here, more and more often there are complaints on the network that when viewing pages through the Firefox browser, an SSL_ERROR_NO_CYPHER_OVERLAP error appears on the screen. In this case, the problem can be both with one specific site, and with all the pages that the user is trying to open.

Why does the error appear?

This error indicates that the browser tried to establish a secure connection to the resource, but it failed. This happens when the site has incorrect SSL and TLS protocol parameters. Also, the problem may not be on the server side, but in the browser itself. If the user changed the settings in the about: config section before this error appeared, then the reason may be this. As a result of changing the system parameters of the browser, the parameters of the security protocols were violated, so the connection could not be established. If the problem is in the browser, then the error will appear not on one specific resource, but on many pages.

Even if the user did not enter the system and hidden settings of the browser, the parameters of the security protocols could be changed without his participation. This happens if the browser functionality has been extended with addons and themes. The addon could independently make certain settings. There are also mentions on the network that the cause of this error may be the wrong system time. If it is set incorrectly, then the browser considers the connection to be no longer secure. Time failure occurs for various reasons, ranging from the actions of virus programs in the system, ending with a worn out BIOS battery, which needs to be replaced periodically.

However, whatever the reason, you can try to fix the problem yourself and restore the browser to normal operation. For this, there are several truly working solutions that will allow you to quickly restore access to reliable and proven resources.

How do I fix the error?

Before resorting to complex settings and drastic changes to the browser, you need to make sure that the problem is not on the server side. You should try to access the same resource using a different browser or device. For example, you can use your smartphone and use it to go to a site that is accompanied by an SSL ERROR NO CYPHER OVERLAP error in the Firefox browser. If the site opens normally from the smartphone and no errors appear, then we can already judge that the problem is on the side of the computer software. If so, you must use one of the solutions below.

Solution 1: reset TLS and SSL settings

In order to reset the security protocol settings, you must initially close all currently running tabs. It is recommended to stop the browser completely and start it again. After that open a new tab and follow these steps:

  1. In the address bar, specify the command “about: config” to go to the system and hidden browser settings.
  2. Accept the security warning to continue.
  3. Enter the TLS parameter in the search bar above the list of settings to open the transport layer connector settings.
  4. In the list of settings, you need to find those lines that are highlighted in bold. This indicates that the default settings have been changed.
  5. Click on the line in bold with the right mouse button and click on the “Reset” option.
  6. If there are several lines, you need to repeat the procedure for each.

ssl error no cypher overlap This procedure must be repeated for SSL, for this, in the settings search bar, enter SSL instead of TLS. Next, you also need to find the lines in bold, and then reset them to the default value. After these steps, all that remains is to restart the browser and try to go to the resource where there was an error earlier. If the error no longer appears, then the problem was precisely in the TLS and SSL settings. They could be changed manually by the user, or the changes were made by one of the browser add-ons. If the problem is not resolved, you need to try the other solution below.

Solution 2: change the fallback TLS version

Changing the TLS version allows you to quickly solve the problem and go to an unsecured site. This is a very good way to quickly get rid of the error, but you need to understand that you need to use it carefully. In order to change the fallback TLS version in your Firefox browser, you need to follow these steps:

  1. Open a new tab and in the search bar enter the command “about: config” to go to the hidden browser settings.
  2. In the search above the list of settings, enter “TLS”, then one by one find the lines below and change their parameters.
  3. Find the line “security.tls.version.min” and set the value to “0”.
  4. Find the line “tls.version.fallback-limit” and also set the value to “0”.
  5. For the parameter “tls.version.max” and set “4”.

ssl error no cypher overlap

By doing this, you will disable the standard security system that was built into the browser by default. The browser will be less protected from external influences, so it is recommended to return all the default values ​​when you have already visited the necessary unprotected resource and no longer need it. If you leave the settings in this form, then you will be more exposed to various viruses and third-party software.

Solution 3: increase browser response time

This error can appear for the simple reason that the server is not able to quickly respond to requests from users. Perhaps the resource is loaded and the servers simply cannot cope with the influx of requests, sending them to the queue. At the same time, your browser has a certain waiting time for a response, if during this time the server does not respond, a corresponding error appears. You can increase the waiting time and thereby solve the problem. To change this parameter, follow these steps:

  1. Open a new tab, enter the command “about: config” in the address bar and press Enter.
  2. Agree to the security warning to continue.
  3. There is a search bar above the list of settings, in it you need to enter “http.tls-handshake-timeout”, and then change its parameter to 30 or 60.
  4. After that, you can again try to enter the resource where the error was, it is not necessary to restart the browser.

ssl error no cypher overlap

This system setting can be left unchanged, but if the problem persists, then it is better to return the default settings, this will speed up the browser and return security to its previous level.

Solution 4: remove addons and themes for Firefox

A very common cause of the problem is various extensions and themes that are installed by the user himself. Each add-on allows you to increase the functionality of the browser, brings certain features that were not there before. Each new theme allows you to refresh the interface and make the work with the browser more enjoyable. However, it is these extensions and themes that often make changes to the system security settings, which is the cause of the SSL ERROR NO CYPHER OVERLAP error. You must disable, uninstall, or try to reinstall extensions.


  1. In your Firefox browser window, hold down the key combination “Ctrl + Shift + A” to go to the desired settings.
  2. You will see a list of installed extensions, you need to disable them one by one, checking in parallel the operation of the resource with an error. You can start with the ones that were recently installed.
  3. Below the settings with extensions there is an item “Themes”, it is recommended to delete everything except the standard theme and try the site’s functionality.

ssl error no cypher overlap

Pay special attention to extensions that block ads or add VPN functionality to your browser. It is this software that most often causes this error to appear.

Solution 5: correct the date and time in the system

The problem may indeed be that the system time and date differ from the real one. Pay attention to the date and time shown in the lower right corner of the screen. A difference even in a couple of minutes can cause this problem. Go to the system settings for date and time to change these parameters. Notice if the time zone is set correctly. It is also recommended to select the automatic time setting, the system will independently determine the correct parameters and set them by default.

If the date and time get lost every time after rebooting, this may indicate that the BIOS battery is worn out. The motherboard has a CR2032 battery that supplies a small 3V power supply to the memory chip, which stores basic BIOS settings, including date and time settings. Replacing this battery is quite simple, but if we are talking about a laptop, it is better to contact a professional to avoid more serious damage.

Additional fixes

If these solutions did not give the desired result, then it is necessary to use additional correction methods. In particular, the following steps must be taken:

  1. Make sure that the network connection is stable and works without failures, if there are problems with the connection to the Internet, then initially you need to solve them.
  2. Check your system for viruses. Run your antivirus software and scan your OS for malware.
  3. Remove software that may affect the browser in one way or another. These are various VPN programs, visual bookmarks, third-party extension panels, etc. This software is often installed without the user’s knowledge when installing another program.

All of these steps can be done on your own, as a result, the SSL_ERROR_NO_CYPHER_OVERLAP error should no longer bother you. If all of the above methods did not help and the resource works fine on another device or in another browser, then a complete reinstallation of Firefox may be required. Remove the browser from your computer, download a new version of it from the official website and initialize the installation without restoring the previous settings.

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