home-made mp4 not visible online.

[rbe]

Hi,
I have a home-made mp4 embedded in a page. It works perfectly on the desktop using Chrome, Safari and Firefox.
But when uploaded, there is no content. The video 'casing' is there, but nothing happens.
I have used a commercial video only yesterday, and that worked fine.
Not sure what I'm doing wrong.
<div class="col-lg-4 d-flex align-items-center justify-content-center position-relative" data-aos="zoom-in" data-aos-delay="200">
<a href="assets/img/training.mp4" class="glightbox play-btn"></a>
</div>
Cheers

 

[rbe]

I've tried using Firefox, Chrome and Safari
The issue can be seen here: https://fcgc.org.au/videotest/index.htm