How to exclude some pages from main menu?

Try looking in your theme’s sidebar.php template file.

tHIS IS SIDEBAR.PHP

[Code moderated as per the Forum Rules. Please use the pastebin]

But sidebar is working properly. Just wanted to remove from menu “Poros, “Myconos”, “HYdra and other pages

Link to sidebar.php

https://pastebin.com/index/T2KgjUTV

Your sidebar doesn’t list Pages by default. Are you using the Pages widget?

Yes. Destinations and Services in sidebar are pages widget.

I changed main-nav.php and it worked perfectly!

From:

<?php
$pages = $wpdb->get_results("SELECT post_name, post_title, ID FROM $wpdb->posts WHERE post_type='page'");
...
?>

To:

<?php
$pages = $wpdb->get_results("SELECT post_name, post_title, ID FROM $wpdb->posts WHERE post_type='page'AND post_status='publish' AND ID in (15,8,22,36)");
...
?>