On scanning the QR code, the page that is opening says "Secure Connection Failed"
The most likely reason to get this error is due to the firewall. Please switch off your WiFi and try via phone data and see if you can access it.
The other reason to get this error can be if the destination URL is not secure (http:// is used instead of https://). You may check the security of your site in the address bar of your browser as shown in the pic below: