When you attempt to visit a secure website (a site starting with https://), Google Chrome must first negotiate a secure, encrypted connection with the website’s server. If Chrome cannot verify the server’s digital certificate, or if the server is using an outdated encryption method that Chrome no longer supports, the browser will block access and display the error ERR_SSL_PROTOCOL_ERROR.
While this error can sometimes be caused by a poorly configured server on the website’s end, it is very frequently caused by a local issue on your computer. Specifically, if your computer’s internal clock is significantly out of sync with global time, Chrome will automatically assume the website’s security certificate is expired. Similarly, a corrupted local SSL state or an overly aggressive antivirus program can hijack the secure connection.
How to Fix the ERR_SSL_PROTOCOL_ERROR in Google Chrome
You should first verify your system clock, and then clear the Windows cryptographic SSL state.
- Check your System Clock: Look at the time and date in the bottom-right corner of your Windows taskbar. If it is incorrect, right-click the clock, select Adjust date/time, and ensure “Set time automatically” is turned on.
- If the clock is correct, you must clear the SSL state. Click the Start button, type Internet Options, and press Enter.
- In the Internet Properties window, click on the Content tab at the top.
- Look for the section labelled “Certificates” and click the button named Clear SSL state.
- A small pop-up will appear stating “The SSL cache was successfully cleared.” Click OK.
- Next, click on the Advanced tab in that same window.
- Scroll down the long list of checkboxes until you find the “Security” section.
- Ensure that Use TLS 1.2 and Use TLS 1.3 are checked. (Do not check older protocols like SSL 3.0 or TLS 1.0, as they are insecure).
- Click Apply and then OK.
Close and restart Google Chrome. Try visiting the website again. With the corrupted local SSL cache cleared and modern TLS protocols enabled, Chrome should successfully negotiate the secure connection without throwing the protocol error.