FBConnect issue

=I have added FBconnect on o开发者_StackOverflow社区ne of my app. Surprisingly for a few users it throwing an error saying: "An error occurred with App. Please try again later"

I could not figure it out why, since it is not occurring with everyone. Say it is happening with 10% of my my users only. Also once I thought this might by something to do with browser. Since few of them reported that it is not working in Firefox/Chrome. But If it is a browser issue then it should be with all of the user.

While I was developing, this error occurred only when I put the facebook application into sandbox mode and therefore the users account didn't have permission to access the app.