Music On Hold Server URI

[metrocommunications]

Looking for some help with setting up a LIVE stream radio to play from the Yealink T4X or T5X series phone.
Need to plug in the following link type ( domain changed for customer privacy reasons ):
http://sub.mydomain.com:80/radio/index.m3u8
When I try this link on the web browser, it plays the live streaming audio.
But it doesn’t work when applied to :
T46G : Accounts/Advances/MUSIC Server URI

SIP URI : sip:music@iptel.org works!
( I tested this one and it works. But my customer’s link doesn’t.)
Some insight on this would be appreciated! Thanks in advance.