ERR_SSL_PROTOCOL_ERROR ("This site can't provide a secure connection") means the secure HTTPS handshake between your browser and the website failed before any page was sent.
Often the website's HTTPS setup is broken, but local issues cause it too: a wrong clock, security software that inspects HTTPS traffic, or an out-of-date browser.
Check if the site is broken for everyone
Try the address in our website checker and in a different browser or device. If it fails everywhere, the website's certificate or server settings are at fault and only the owner can fix them.
Fixes on your device
- Check your date and time. Certificates are only valid between set dates, so a wrong clock breaks HTTPS. Turn on automatic time.
- Try Incognito mode to rule out extensions and cached data.
- Clear browsing data (cookies and cached files) for the site.
- Clear the SSL state on Windows: open Internet Options, then the Content tab, then Clear SSL state.
- Turn off HTTPS scanning in your antivirus, or pause it briefly to test.
- Disable your VPN or proxy, then try again.
- Update your browser and operating system. Old versions may not support the encryption that modern sites require.
If you own the website
Check that your certificate is valid and installed with its full chain, that the server supports TLS 1.2 or 1.3, and that port 443 really serves HTTPS (not plain HTTP). Free tools such as SSL Labs' server test show exactly what's wrong.
Questions
Is ERR_SSL_PROTOCOL_ERROR dangerous?
The error itself protects you: the browser refused to continue because it couldn't set up a secure connection. Don't enter passwords or payment details on a site that shows it.
Why does only one website give me ERR_SSL_PROTOCOL_ERROR?
That site's HTTPS configuration is probably broken, or your security software is interfering with it. Test it on another device to tell which.