i did had serious problems connecting to kong the last 4 days always getting a connection failure. Today i found some time to dig into that problem for which i found a solution within 2 minutes.
After a short ping to www.kongregate.com i got the error that the host could not be found. So i changed the used DNS server in my router configuration to use a specific one instead of the default DNS server provided by my provider (i am now using 18.104.22.168). After restarting my router everything worked fine again.
Hope this might help you.