When first prompted tap Allow on the “App Would Like to Access the Camera” dialog.
If you’ve already denied access follow these steps on your Android or iOS device:
iOS
Open Settings → Privacy & Security → Camera
Enable camera access for the Fernox App
Relaunch the app to confirm the change
Read more: https://support.apple.com/en-gb/guide/iphone/iph168c4bbd5/ios
Android
Open Settings → Apps & notifications (or Apps)
Manage Apps → Fernox App → Permissions
Tap Camera → choose Allow only while using the app
Relaunch the app to confirm the change
Read more: https://support.google.com/android/answer/9431959?hl=en-GB