Can't select custom template for new page

Hello, I am new to WP.

My question is that, as learned from the instruction of WP documentary, I created a new template for the page to used. But after I put the file in template folder. I still can find it in adding new page template drop down box while I can see it is there in “Appearance>>editing”. On WP official website it says that “Note: when creating or editing a Page, the Page Template option does not appear unless there is at least one template defined in the above manner.” If it is true… How can I get my new template for the page ?

the following is the syntax of my new template
=======================================================================
<?php
/**
* Template Name: subscription
* The main template file subscribe through email
*
* @package WordPress
* @subpackage YEN
*/
?>
=======================================================================