Auto Close

Check "Yes" if you want the In-Video ad popup to close automatically after a duration of "X" seconds (duration is set in seconds via the "Duration of Ad" field).

If you leave it blank (for "No"), that means the video will not automatically close.

So you should enable the "Allow Closing" option. If not, the ad will be stuck on screen,a nd the viewer will not be able to continue watching the video any further.