Unable to load camera for the first time I open the application in Xamarin.Forms

Hi all,
I am developing an application in Xamarin.forms.In that I am using camera.Whenever I try to open the camera after installing my application,its showing a blank page.If I restarted the app its working fine and I can see the camera.This is happening every first time I installed the application.
Can anyone please help me out of this situation.
Thanks in advance.