Button doesn't unlock in IE11

Hi all,

I just created a course that has several custom block pages. Each page has a video with a locked "Continue" button—thus making the learner watch the whole video before they can move on.

Everything works great in Chrome, but when you watch the video in IE11, the button doesn't unlock, so you can't move forward.

Any idea why it's doing that? Our entire company uses IE as a standard.

Thanks,

Kristen