Remove this permission
<uses-permission android:name="android.permission.CAMERA"/>
I faced this error executing my app in android 7. After tests I noticed user permission wasn’t in project A but it was in project B, that I only tested in android 5 devices. So I remove that permission in project B in order to run it on other device that targets android 7 and it finally could open.
In adittion I added the fileprovider code that Android suggests here https://developer.android.com/training/camera/photobasics.html
Hope this helps.