It seems I’ve run into the same issue with my background video…
Works on mobile, but not on my desktop/laptop; which is quite strange.
Edit:
A possible solution straight from the Webflow support:
“A recent issue popped up with background videos not playing when reduced motion preferences are enabled on some computers. It’s possible that reduced motion/animation preferences are preventing the videos from playing in these cases.”
In Windows: Settings > Ease of Access > Display > Show animations in Windows.
On Mac:Apple menu > System Preferences, click Accessibility, then click Display.
Changing these settings on my desktop (Windows 10) fixed it for me. My best guess is that a recent update changed these settings.