How to change static page to static post in sub domain setting.

How can i show single post in sub domain homepage.
just like page selecting from sub domain setting like
Setting >> Subdomain Setting >> Customize >> “A static page >> Front page:”

I have changed to :

$r = isset($this->selected_categories[$this->id_subdomain]['front_page']) ? $this->selected_categories[$this->id_subdomain]['front_page'] : '';	

		$posts = get_posts(
        array(
            'post_type'  => $post_type,
            'numberposts' => -1,
            'category' => $this->id_subdomain
        )
    );
    if( ! $posts ) return;

    $out = '<select id="mcs_categories[front_page]" name ="mcs_categories[front_page]"><option>Select a Page</option>';

    foreach( $posts as $p )
    {
    	if($r == $p->ID )
    	{$select = 'selected="selected"'; }
        $out .= '<option ' . $select  . ' value="' . $p->ID . '">' . esc_html( $p->post_title ) . '</option>';
   		$select = '';
    }
    $out .= '</select>';
    echo $out;

but in front page it not displaying post .
it is giving page not found error

https://www.ads-software.com/plugins/main-category-as-subdomain/