Among the most common errors in the browser Google Chrome, Microsoft Edge, Opera, Yandex Browser when opening sites or certain sections in them is the message “This site cannot provide a secure connection. The site is using an unsupported protocol “with error code ERR_SSL_VERSION_OR_CIPHER_MISMATCH, and in detail -” The client and server support different versions of the SSL protocol and cipher suite. ”
This manual details how to fix the ERR_SSL_VERSION_OR_CIPHER_MISMATCH error for different situations and browsers: both for “regular” sites and for various government sites, where the problem may be of a different nature.
- Solution for ERR SSL VERSION OR CIPHER MISMATCH
- ERR SSL VERSION OR CIPHER MISMATCH error for government sites with encryption according to GOST
- Video instruction
Solving the problem “Unsupported protocol” ERR_SSL_VERSION_OR_CIPHER_MISMATCH
In general, an error occurs when establishing an encrypted connection to a site at the TLS Handshake stage. If the site uses an encryption protocol or key length not supported by your browser, the result is an ERR_SSL_VERSION_OR_CIPHER_MISMATCH error.
If an error appears when accessing a regular website on the Internet: not a website of a government agency, a bank, or a procurement service, you can use the following methods to fix the problem (the methods are described for Windows 10, Windows 11 and previous versions):
- Press the Win + Rkeys on your keyboard (Win is the Windows logo key), type cpl, and press Enter. On the Advanced tab, enable TLS 1.0, 1.1, 1.2 and 1.3 if not active. Also try enabling SSL 3.0.
- For the Google Chrome browser: open the chrome: // flagspage (enter this address in the address bar and press Enter), search (in the field at the top of the page) for the word TLS and disable the “Enforce deprecation of legacy TLS versions” option (set to Disabled) , do the same for the Experimental QUIC protocol parameter. After that, click on the button that appears to restart the browser.
- Clear SSL: just like in the first step, open the Internet Properties window (Win + R – inetcpl.cpl) and click “Clear SSL” in the “Contents” tab.
- If your computer uses a VPN or proxy, disable them. Moreover, for the proxy system parameters, disable the “Automatic detection of parameters” option – in the same window as in the previous step, go to the “Connections” tab, click “Network settings” and uncheck if it is checked.
- The network protection features in third-party antiviruses can also be the cause of the problem – try temporarily disabling them if available.
- Try clearing your browser cache and cookies. In Google Chrome, this can be done by pressing the Ctrl + Shift + Deletekeys and confirming the deletion of the data. Or in the section “Privacy and security in the browser settings.
- Using an old operating system (for example, Windows XP) without the possibility of newer versions of browsers and without built-in support for new encryption protocols may lead to this error. You can try to access the site via the http protocol; for this, manually change the https: // to http: // in the site address
If the described methods did not help, then in theory the cause of the problem may be a very old version of the browser (especially if you are using the portable version), or problems with the site itself, in particular with the SSL certificate and encryption it uses. But in this case, the methods described in the next section for sites with encryption according to GOST can help.
Attention: if the problem occurred with a single site and was not previously observed, the problem may be temporary, for example, when changing the IP address of the site, changing the security certificate, and other actions by the administrator. In such a situation, the problem usually disappears after a while.
ERR SSL VERSION OR CIPHER MISMATCH error for government sites with encryption according to GOST
Among the sites, when accessing which the browser can issue the indicated error, are various sites of government agencies, sometimes banks, in the recommendations for access to which the Internet Explorer browser is usually indicated (by the way, its use can really solve the problem, but this is not always possible). If you also encountered an error when opening such a site, the possible options are:
- Use Yandex Browser (it supports encryption according to Russian GOSTs) or Chromium Gost – https://www.cryptopro.ru/products/chromium-gost
- Carefully study the information on the problem site: in particular, the help may indicate the need to install certificates on the computer with instructions on how to do this.
