This error can be caused for different reasons regarding your browser or internet connection.
How to fix an ERR_CONNECTION_CLOSED
1. Check your internet connection
You might have to switch from WIFI to a cable connection or reset your router.
2. Check if site is down
3. Check browser
You might try to access the website from a different browser, or you can delete the current browser cache and try again. Maybe you have a browser plugin that blocks the website.
4. Temporarily disable antivirus and firewall software.
Check if your antivirus or firewall software is blocking the website.
5. Reset the TCP/IP settings
Execute netsh int ip reset, reset the Winsock interface netsh winsock reset and restart the computer
6. Disable proxy server and VPN connections
You might have to disconnect from your proxy or VPN connection and try again to connect.