When you use SightCall or Visual Support app for the first time, iOS will prompt a window asking if you would allow the app to have access to the microphone and camera. Sometimes, this prompt window can disappear quickly or the user may accidentally tap the wrong area on phone screen that causes the prompt window to disappear and the app ends up not having access to mic and camera.
In such scenario, you can apply the following steps to make sure SightCall or Visual Support app has all the access needed:
1. From the iPhone main menu, click Settings.
2. Scroll down until you see SightCall or Visual Support app and click it to go to the app settings.
3. Make sure SightCall app has access to Local Network, Microphone, Camera, Background App Refresh, and Cellular Data.