What is Err_spdy_protocol_error? ERR_SPDY_PROTOCOL_ERROR indicates that the web page you’re trying to access is unavailable, which indicates that the browser no longer supports the SPDY protocol.

Check if error ERR_BAD_SSL_CLIENT_AUTH_CERT still occurs. Solution 4: Check for and Install Windows Update (If Available) An outdated Windows operating system can also cause issues on your computer.

So, if you do not know what you are doing while following any fix, it is recommended that you skip it and move on to a potential fix that you understand. What causes ERR_SSL_VERSION_INTERFERENCE?

When the browser version is up to date try checking if the issue still occurs. Method 2: Check the Firefox encryption protocols to fix ssl_error_no_cypher_overlap ...