help

Hi, why this is not working?

add_action('um_submit_form_errors_hook_','um_custom_validate_username', 999, 1);
function um_custom_validate_username( $args ) {

	global $ultimatemember;

    $number = preg_replace('/[^0-9]/', '', $number);

	if ( isset( $args['user_login'] ) && ((!strstr( $args['user_login'], 'E00') && strlen($args['user_login'] =='9')))) {
		UM()->form()->add_error( 'user_login', 'This user login is not valid.' );
	}

}

thanks for your help.