Problem using add_submenu_page

Hi

I am trying to develop a plugin. In this plugin I want to add a submenu under Dashboard. I can see the submenu link whenever I am logging in using my super admin id. But other users can’t see the same link at their Dashboard whenever they are logging into therir account.
The url is
https://bluelinc.net/wordpress/wp-admin/index.php?page=advert

The code to display the link is
[Moderator note: snipped code block, please use the pastebin as per the Forum Guidelines]

Please reply.

Regards

Gargi.