why is my camera not working

[AC Question]

When i go on to my camera it say ur camera has stopped due to apps or security policies i no its not the apps what do i do to fix this

 

[ldwhitley]

That happens to my phone too at times. Its a Nexus 5 and now at Marshmallow, but happend lollipop too. I found that if I powered the phone off and then turned it back on - the camera worked again.