The video in the Video Lightbox is hosted on Vimeo and loads fine and autoplays on desktop and on mobile when connected to WiFi. When I’m connected via 5G on an Iphone, it won’t load – the circle just keeps spinning. The Video in the Video Player is exactly the same video but plays fine when you press the play button.

The first video in your demo which I assume is self hosted, autoplays fine. The other videos are YouTube and open with the red play button, so aren’t autoplay on mobile. On desktop they autoplay when lightbox opens.

I have exactly the same video that works fine on 5G which you can see here https://paulsurety.co.uk/own-your-journey-lewis-hamilton. This site is not built on Salient and uses a different Video Lightbox.