If you get this message (see image) on your Iphone while trying to enter a meeting room, you will have to check what's wrong.
1. Go to settings and search for safari while scrolling down.
2. Make sure that 'camera and microphone access' is active. If it's not active yet, you will have to activate it.
3. Once you've activated this setting, the camera and microphone should work in Safari.
If this doesn't help, you can try to close all apps and all the tabs in your browser.
So Vectera would be the only place that asks for your camera and microphone.