Firefox was configured to try to use IPv6. IPv6 is a new version of the IP protocol, and it isn’t supported on my network. Therefore what was happening was that Firefox would try to use IPv6, wait until the request failed, and then try IPv4. To fix it I followed this procedure:
:rock: :marchmellow: :rock: :marchmellow::rock:
- Open a new tab by typing Ctrl-t
(That’s the Ctrl key on your keyboard and the letter t key at the same time) - Enter about:config in the address bar of Firefox
- Enter ip into the Filter: text box
- Look for the network.dns.disableIPv6 entry in the table below the Filter: text box
- Double click the network.dns.disableIPv6 entry
- Restart Firefox
:rock: :marchmellow: :rock: :marchmellow::rock: