Super strange … I was able to access facebook.com but I could not reach business.facebook.com to do Facebook Ads. All other websites seemed to be ok.

This was the message I got:

This site can’t be reached The connection was reset.
Try:

Checking the connection
Checking the proxy and the firewall
Running Windows Network Diagnostics
ERR_CONNECTION_RESET
Check your Internet connection
Check any cables and reboot any routers, modems, or other network devices you may be using.
Allow Chrome to access the network in your firewall or antivirus settings.
If it is already listed as a program allowed to access the network, try removing it from the list and adding it again.
If you use a proxy server…
Check your proxy settings or contact your network administrator to make sure the proxy server is working. If you don't believe you should be using a proxy server: Go to the Chrome menu > Settings > Show advanced settings… > Change proxy settings… > LAN Settings and deselect "Use a proxy server for your LAN".

After losing hours doing things like

  • clearing browser cache
  • doing ipconfig command (flushdns, renew ip)
  • rebooting modem to get another ip
  • testing in other browsers: firefox, edge, …

The only browser where it seemed to work was my epic browser with uses a proxy.

So it MUST have to do something with my ‘local’ network settings.

Long story short.

In the “Internet Protocol Version 4 (TCP/IPv4) Properties” of my LAN interface (Networking) window.

So the DNS IP’s (208.67.222.123 and 208.67.220.123) used in the screenshot above come from OpenDNS and somehow they don’t work for business.facebook.com. So I turned it off and changed it back to “Obtain DNS server address automatically”.