Anyone else getting 'Connection Request Failed 407'? How to fix it?

Ugh, the 407 error is such a pain. I fixed mine by updating my network settings.

Go to your network adapter settings > Properties > Internet Protocol Version 4 (TCP/IPv4) > Advanced.

Then, under the "WINS" tab, disable NetBIOS over TCP/IP.

Worked for me, but YMMV. Let me know if it helps!