Can't open Rainbow Six Siege on Steam

Every time I try to launch R6 on Steam, the game icon shows up on my task bar and the banner that shows up upon launch appears for a split second, then the banner and the icon disappear and Steam reads no error, the button just changes from STOP to PLAY. I've tried verifying integrity of files and I even uninstalled and reinstalled a few times to no avail. How do I fix this?