Problem With Creating a Video Question on Pavlovia

When I try to upload a video to Pavlovia. I receive the following message and all the video files on my computer are inaccessible:

I tried changing the video file format, but none of the other major ones worked either. The only solution that I have found is to upload all the clips to Youtube.

However, if including a Youtube link, participants are able to access and watch the video as many times as they like. It is important to my study that participants can only view the video once before answering. I have tried embedding the Youtube videos with an autoplay and adding a timer to the question page but, once the timer runs out, the survey does not proceed onto the next page as I hoped.

Is there a way to upload a video file and/or adjust the logic on Pavlovia so that participants can only view the video once?

Thank you for your help!