Fiddler can't connect to domains with 3 consecutive hyphens.
This error occurs:
fiddler.network.https> HTTPS handshake to r1---sn-ab5szn7e.googlevideo.com (for #793) failed. System.ArgumentException Decoded string is not a valid IDN name.
Parameter name: unicode
Start Fiddler Everywhere (at least on Mac), make sure HTTPS decryption is enabled.
Go to www.youtube.com and try to watch a video.
The aforementioned error will occur in Fiddler.