php page not found for plugin options menu

Looking at an old commit on a plugin I am writing, I am seeing a couple of things that jump out at me.

First is your options page declaration. I had mine as follows, using your labels:

function settings_menu_email() {
    add_menu_page(
        'Set Email',
        'Set Email',
        'manage_options',
        'email_admin_menu',
        'email_admin_menu_callback',
    );

    add_submenu_page(
        'email_admin_menu',
        __( 'Options', 'textdomain' ),
        __( 'Options', 'textdomain' ),
        'administrator',
        'email_admin_menu_options',
        'email_admin_menu_options_callback'
    );
}
add_action( 'admin_menu', 'settings_menu_email' );

Then define your settings groups outside of the callback function.

function email_initialize_plugin_options() {
    add_settings_section(
        'email_settings_section',
        'EMail Options',
        'email_options_callback',
        'email_admin_menu_options'
    );

    // Add Email Address Option
    add_settings_field(
        'email_settings_section',
        'EMail Address',
        'email_set_address_callback',
        'email_admin_menu_options',
        'email_settings_section',
        array(
            'Enter a description here...',
        )
    );

    // Register Email Address Option
    register_setting(
        'email_settings_section',
        'email_settings_section'
    );
}
add_action( 'admin_init', 'email_initialize_plugin_options' );

Then you do your callbacks.

In order to test this, just add empty callback functions.