Had this problem suddenly manifest itself to me - and on ALL Browsers... so sussed out that Betfair had changed something.
It looks like their Picture providers - But ONLY for UK Horse Racing - need to drop a COOKIE on your computer for Live Video to work on UK Racing - Somewhat perversely - Live Video for American Racing works perfectly WITHOUT said Cookie.
I eventually UNblocked - ' BLOCK third-Party Cookies' - which i ALWAYS DO by choice and INTENT - on just ONE Browser - (I use several DIFFERENT Browser) - that I now use almost solely for 'Live Video', and keep separate from OTHER main Browser uses - and Live Video now works.
KEEP 'BLOCK Third Party Cookies' on ALL your other main Browsers - apart from the Browser that you just use mostly for 'Betfair Live Video'- to maintain your Privacy and keep TRACKING COOKIES OFF your computer.
To do the above - you will either need to access 'Live Video' (separately) via ...
https://livevideo.betfair.com/
OR - Allow 'Third-Party Cookies' access on the Browser that you use for Betfair - and the 'Live Video' Link from the Market frame... But you will then ALSO be allowing 'Third-Party Cookies' from any ALL other sites that you use/visit on that SAME Browser.
The choice is yours.
Had this problem suddenly manifest itself to me - and on ALL Browsers... so sussed out that Betfair had changed something.It looks like their Picture providers - But ONLY for UK Horse Racing - need to drop a COOKIE on your computer for Live Video to