We tried the service last night. It worked fine on our laptops and on Android+Firefox. However, on iPhone 6 with iOS 12.4.9 with Safari, it did not connect. (We also tried iOS 12.5 as well as iOS 12.4.9)
Here's what happened: I went to the webpage, copied the link, sent it to the iPhone user. They clicked and came to the webpage, but it simply said "Waiting for connection" for a long time (over a minute, all on the same local wifi network). There was no webcam image visible for them.