Question: I have implemented FB in my application an it is working perfectly in my samsung device o/s 1.5. However in the HTC Evo the FB login dialog disappears soon after loading. it stays for a couple of seconds and vanishes. i have tested it in the emulator 2.2 and it works fine. 

what could be the possible reason of the behavior and how can i overcome it?

just found out that it happens when i am logged into facebook in another application. 
however in applications like photoshop express there is no such issue.

Just what am i missing??

Answer: 
The issue is actually that you haven't set up your Key Hash for your application with Facebook yet which is required to use SSO. FORCE\_DIALOG\_AUTH actually disables SSO, but this is a poorer user experience. Instead, take a look at an article I put together after struggling with this issue which describes the correct way to tackle your problem:

<http://sean.lyn.ch/2011/07/android-the-facebook-sdk-sso-and-you/>
I got this FacebookException because of [developers site](https://developers.facebook.com/) was not working.After developer facebook site worked, this issue was resolved.