Here's a somewhat related question,
Why is Google forcing a broken cipher (RC4) in Youtube?
IE11 disables RC4 completely.
Specifically, the server that actually serves the video only accepts RC4 connections over TLS. You can also connect to the same server over plain HTTP. See
https://support.mozilla.org/en-US/questions/990082
r19---sn-ab5l6nel.googlevideo.com
Specifically, the server that actually serves the video only accepts RC4 connections over TLS. You can also connect to the same server over plain HTTP. See https://support.mozilla.org/en-US/questions/990082 r19---sn-ab5l6nel.googlevideo.com