Razer BlackWidow v4 leds not working.

Try to hard reset it: https://mysupport.razer.com/app/answers/detail/a_id/1697/~/how-to-fix-an-unresponsive-razer-keyboard-with-a-hard-reset-or-by-exiting-out#:~:text=Press%20and%20hold%20%22Escape%22%2C%20%22Caps%20Lock%22%2C%20and%20the,hold%20%E2%80%9CEscape%E2%80%9D%2C%20%E2%80%9CCaps%20Lock%E2%80%9D%2C%20and%20the%20space%20bar.

But it may be a physical issue with the LED itself.

Thanks for the replay.   I used the steps from the video and the issue continues.  I think is an issue with the LED itself.

I have been having the same issue, it occurred on my relatively new blackwidow V4 pro.  It had multiple keys LEDs fail.  I plan on returning it since its under warranty, but i bought another one in the downtime, planned on moving the repaired or replaced one to a different computer when i got it back.  The new one had an LED fail in the G key within a week of use.  There's something going on with the newer Razer keyboards, i have never had this issue on any razer keyboard i owned before, not my blackwidow V1 or V2.  seems to be poor QC.  Hopefully they figure this out,   

Same issue here. I’ve had my BlackWidow v4 Pro for exactly 2 years now and as of today I have 20 failed LEDs - some don’t turn on at all while the majority have lost 1 or 2 colours. It’s quite frustrating considering the price of the keyboard. I don’t think I’ll be buying another Razer product because 2 years is really not an acceptable period of time to have this many LEDs fail. I’m going to try and get new LEDs and solder them in place of the failed ones but it’s a fiddly job which I’d rather not have to do.