Your endpoint is only applied to posts, add EP_PAGES to generate rules for page post type-
add_rewrite_endpoint( 'amp', EP_PERMALINK | EP_PAGES );
That should also be within a function hooked to init.
Related Posts:
- Get template name by full URL
- Template Include crashing browser
- problem including page template
- Include Template Based on User IP Address
- unexpected T_FUNCTION in plugin template [closed]
- Use TEMPLATEPATH for custom url
- php include returns 1 after content
- Is there any way to use get_template_part() with folders?
- Methods of Integrating Plugin Data with Themes
- Use template_include with custom post types
- template_include for search.php makes WordPress think its on the home page
- Render a different post/template from within the template_include action?
- Custom Endpoint Gives 404 Header
- WordPress rewrite rules for state and city
- template_include not loading -instead goes to index.php
- Link to file in plugin directory from wordpress template?
- Is it safe to include a javascript file in a template’s php file?
- How to check if txt file exists inside template folder?
- For custom templates, is it better to use `template_include` or `type_template`?
- Put CSS inside a PHP file and include it the right way
- locate_template function – File not getting included
- How do I go about looping through a advanced custom field on a particular page inside of another page
- Content vs Template on custom post
- A include_template Question
- template_include filter does not render the custom template
- How to use template_include hook with form submission?
- WP overwrites my setup_postdata() setup
- Replace wp_query with wp_user_query
- Pull in an “Include” file based on a WordPress Category ID
- template_include doesn’t work with child theme
- How to include a page template and template part into my plugin
- Should I use do_action in the header file?
- Redirect page to homepage, keeping URL
- How to add variables to a template
- Why is WP template_include overwritting all templates rather than specified page?
- require happens out of order
- Using require_once for parent-directory not working but is working in sub-directories
- Theme parts path location dump
- wp_mail: Using file_get_contents to include template in message
- Why does get_post() return the latest post inside template_include before doing anything
- Should I use include(_once) or require(_once) for loading php-file with customizer settings?
- How do I update the SEO information on dynamic pages being generated from template_include?