Steps that I've tried,
1) Generated the keyhash (although i got a warning/error as "keytool: command not found") from the official developer documentation.(keytool -exportcert -alias YOUR_RELEASE_KEY_ALIAS -keystore YOUR_RELEASE_KEY_PATH | openssl sha1 -binary | openssl base64
)
2)Also tried the the keyhash shown in the error message while signing in.
Still, none of the above keyhashes worked, interesting i was successfully able to signin to facebook in my debug version. Please Help