The reason
On iPhone and iPad, every browser (Safari, Chrome, Edge, Firefox) uses Apple's engine, and Apple does not provide web pages any access to USB devices. The viewer detects this and tells you so. It is not something a different browser or a Lightning or USB-C adapter changes.
What works
- The maker's native app (UseePlus / USee camera) is the only way to plug the camera straight into an iPhone. The camera's USB interfaces are built for Apple's accessory protocol, which is what that app uses.
- A Mac, Windows PC, Linux box, Chromebook or Android phone with Chrome or Edge: that is where the viewer runs.
- Watch on the phone, camera on the computer: run the viewer on a laptop and look at the laptop. There is no streaming-to-phone feature in the viewer, by design: the video never leaves the machine the camera is plugged into.
Try it
Open the viewer Chrome or Edge on a computer, or Chrome on Android. Nothing is uploaded.