I recently encountered this issue on my Dell XPS 17 after trying to boot OBS and fixed it in the following way. I'm not an expert on OBS or graphics displays but I wish to share how I fixed it for my case and hope it works for you as well.
I first searched "Device Manager" from the Search Bar and then found that I had 2 display adapters. I disabled the one I knew which was not being used by my laptop monitor (my case was NVIDIA) then when I tried OBS and it ran fine.