Issues with Video Playback (no audio on Laptop or mobile devices)

Hi all,

SharePoint Online

Have tried a variety of devices and browsers.

My issue is with video playback regarding uploaded videos; on Desktop uploaded videos play perfectly. However when viewing the same pages/files on Laptops or mobile devices the video plays, but there is no audio.

I can't fathom why this is the case, I have tried viewing the files in both File viewer and Document Library web parts but to no avail.

Is this a known issue? Has anyone else encountered this before?

Thank you.