Why isn't my background video playing on mobile devices?
Splash background videos are visually appealing, but can be complicated to deal with on mobile devices.
If you're using a YouTube video as a Splash background, by default when your clients view your page on a mobile device, they'll see the video's thumbnail image. If you're the owner of the video, you'll want to make sure to set a thumbnail image for the video.
If you have admin access to the video, you'll be able to set or change the thumbnail image via the video settings on YouTube's side.
If you have a thumbnail set but it's not showing in Qwilr, make sure you're using the full YouTube URL in your Qwilr Page. It should look something like https://www.youtube.com/watch?v=f2s-gi1BZ0o . (Note that the URL contains the full youtube.com rather than a shortened URL like https://youtu.be/f2s-gi1BZ0o.)