I have followed the instructions here:
The developers of this app have not set up this app properly for Facebook Login?
Made my app public and the circle is
STEP 1:
In Settings -> Basic -> Contact Email. (Give your/any email)
STEP 2: in 'App Review' Tab : change
Do you want to make this app and all its live features available to the general public? Yes
And cheers ..
2020 UPDATE
Visit https://developers.facebook.com/apps/ and select your application.
Go to Settings -> Basic. Add a Contact Email and a Privacy Policy URL. The Privacy Policy URL should be a webpage where you have hosted the terms and conditions of your application and data used.
Toggle the button in the top of the screen, as seen below, in order to switch from Development to Live.
Issue Log: App Not Setup. This app is still in development mode. and you dont have access to it. register test user or ask an app admin for permission
HOW TO CHANGE TO LIVE MODE
1. go to : https://developers.facebook.com
2. select your app on "My Apps" List
3. toggle the switch from OFF to ON
HOW TO ADD AS TEST OR ADMIN
1. go to : https://developers.facebook.com
2. select your app on "My Apps" List
3. go to : Roles > Roles > Press Add for example administrator
4. Search your new admin/tester Facebook account.
5. admin must enter facebook password to confirm.then submit
the new admin must go to developer.facebook page and accept the request
6. go to : https://developers.facebook.com
7. Profile > Requests > Confirm
8. Congratulation you have been assign as new Admin
HOW TO GET AND SET HASHKEY FOR DEVELOPMENT
as Refer to Facebook Login Documentation
https://developers.facebook.com/docs/android/getting-started/#create_hash
The most preferable solution by me is by code ( Troubleshooting Sample Apps )
it will print out the hash key. you can update it on
https://developers.facebook.com/apps/yourFacebookappID/settings/basic/
on Android > Key Hashes section
a step by step process on how to get the hashKey.
Firstly Add the code to any oncreate method
Run The app and Search the KeyHash at Logcat
step by step process on how Update on Facebook Developer.
Open Facebook Developer Page. You need access as to update the Facebook Developer page.
https://developers.facebook.com
Follow the step as follow.