Greetings @NotSahilRaja
Welcome to the Unreal Engine Community Forum. I’ve saw this issue on a number of occasions with DX12. Sometimes it’s something as simple as doing a full reset to default on NVidia Control Panel that fixes it and other times it’s been things such as the GPU not being seated well, RAM incompatible with the motherboard, etc. If you try swapping the project to DX11 it may also resolve it. But, in some cases people want to keep DX12 for some of the new features. I’d check those areas if you haven’t. (Especially if this is a custom built PC or you’ve changed the RAM etc)