Having the exact same problem. Windows is recognizing the bluetooth plug in, the blue light is blinking, but I sit and wait and it won’t pair and eventually the headset just shuts itself down again due to inactivity. 

I’ve been waiting for over two months for the dongles to restock, then had to go through a bunch of trouble to get a new usbc to usb converter so the damn thing could actually be plugged in to a normal computer, and now it still won’t work and I have no idea why. I’ve tried to follow every step in the pairing guide. I made sure I bought a dongle that is fully compatible with Razer Barracuda X. I am simply at a loss. I’ve submitted a support ticket and hope that will provide some help, but if it doesn’t I will be sending the entire headset and dongle back and asking for a replacement of both that come already paired, because I simply don’t know what else to do. 

Also, as a follow up, I tried using the 3.5 mm connection to bypass the bluetooth, but that will not work - the headphones work, but not the microphone. So even though it has a 3.5 mm jack, it is useless for the mic. I have tried any and all combination of splitters to fix that as well, while waiting for the dongles to be sold again. 

Have you used the Headset Pairing Utility software?

https://mysupport.razer.com/app/answers/detail/a_id/5994/~/how-to-use-the-razer-headset-pairing-utility

It happened to me something similar. My headphones are just fine, they work perfectly but my dongle just broke a few days ago. I bought a new dongle that it is supposed to work with the majority of the razer headphones. I installed the pairing utility but for some reason the app doesn't recognise the new dongle. The strangest thing is that my PC does, but not the pairing utility app. I followed all the app instructions but nothing. I'm desperate, so I hope I could get some help here.

I’m having the opposite issue…. it recognizes my dongle but not my headset. i have one pair that is fully functional and for giggle i tried it...still only recognizes the dongle…weird