Have you tried
add_action( 'init', array( $this, 'auto_sign_in') );
__CLASS__
returns the class name, not the class instance, so it only works for static functions.
Have you tried
add_action( 'init', array( $this, 'auto_sign_in') );
__CLASS__
returns the class name, not the class instance, so it only works for static functions.