Monitor flickering while playing Fortnite

[vepayloaslefe1i]

My friend's monitor started flickering with a white light when we launched Fortnite. We've tried unplugging the monitor, restarting the PC, and adjusting display settings, but nothing has worked. I searched online for solutions but found nothing helpful. The monitor had no issues before and only started flickering after clicking play, so we don't think it's a wiring problem. Any help would be appreciated.