iPhone only starts live camera feed once then won't respond

After a ton of trials, finally got camera working again by changing WiFi name (that's random) but now my iPhone 8 will play live feed one time and then the button won't work again unless I completely close out app running in background and redownload app. Works fine on all my other devises, including my husbands identical phone! Tried everything SimpliSafe reps recommended and they just shrugged and said....oh well. Tried hard reset of phone, uninstalling and reinstalling camera, delete and redownload app a bunch etc.....What is happening? Also when I tried to have two cameras, it would only live stream one and the one that played, same deal....one shot and then if I wanted to do a second live stream...nope- unless I delete and redownload app....