VR Preview is not appearing

HelloEveryone, 
I'm using Rift S., When Connected to the PC and when I open UE 5.0 project files not able to get a preview, but when I open UE 4.27 project files it shows a VR preview.  
What's the issue I don't exactly.

and my Oculus app in the setting I'm not able to set can't set Oculus as active openxr runtime, when I click on set as Oculus nothing will show neither it is turned on or off.

Kindly need help