Hi there,
Cloudflare CDN is not meant to cache video. Please read the following terms:
Content Delivery Network
Content Delivery Network (Free, Pro, or Business)
Cloudflare’s content delivery network (the “CDN”) Service can be used to cache and serve web pages and websites. Unless you are an Enterprise customer, Cloudflare offers specific Paid Services (e.g., the Developer Platform, Images, and Stream) that you must use in order to serve video and other large files via the CDN. Cloudflare reserves the right to disable or limit your access to or use of the CDN, or to limit your End Users’ access to certain of your resources through the CDN, if you use or are suspected of using the CDN without such Paid Services to serve video or a disproportionate percentage of pictures, audio files, or other large files. We will use reasonable efforts to provide you with notice of such action.
If you want to stream video, you can do so by using Cloudflare stream:
Cloudflare Stream
Stream
Alternatively you can also stream video from an unproxied record, but it will not be Cloudflare accelerated, protected or have any of the Cloudflare features enabled:
Having said this and after checking your media file, your issue is likely the same as this one:
Take care.