Can't create new pages in wordpress

Question

I have ran a php code to remove some pages of the database, the code worked fine and i have left with the optmised pages i needed.

However, now i can’t create new pages at all.

This happened with 2 sites now, The first website (catering.jobs), the fornt end gives:

        Warning: Attempt to read property "post_type" on null in /wp-includes/post.php on line 7618

        Warning: Attempt to read property "post_type" on null in /wp-includes/post.php on line 7619

        Warning: Attempt to read property "ID" on null in /wp-includes/post.php on line 7623

        Warning: Attempt to read property "post_type" on null in /wp-includes/post.php on line 7868

        Warning: Attempt to read property "post_type" on null in /wp-includes/theme.php on line 3532

        Warning: Attempt to read property "post_type" on null in /wp-includes/theme.php on line 3757

        Warning: Attempt to read property "post_type" on null in /wp-includes/post.php on line 5405

        Warning: Attempt to read property "ID" on null in /wp-includes/post.php on line 5405

        Warning: Attempt to read property "post_type" on null in /wp-includes/post.php on line 4706

        Warning: Attempt to read property "post_type" on null in /wp-admin/includes/post.php on line 709

        Fatal error: Uncaught Error: Attempt to assign property "post_content" on null in /wp-admin/includes/post.php:748 
        Stack trace: #0 /wp-admin/post-new.php(66): get_default_post_to_edit('page', true) #1 {main} thrown in /wp-admin/includes/post.php on line 748

The error log gives:

         Got error '
    PHP message: PHP Warning:  Attempt to read property "post_type" on null in /wp-includes/post.php on line 7618
    PHP message: PHP Warning:  Attempt to read property "post_type" on null in /wp-includes/post.php on line 7619
    PHP message: PHP Warning:  Attempt to read property "ID" on null in /wp-includes/post.php on line 7623
    PHP message: PHP Warning:  Attempt to read property "post_type" on null in /wp-includes/post.php on line 7868
    PHP message: PHP Warning:  Attempt to read property "post_type" on null in /wp-includes/theme.php on line 3532
    PHP message: PHP Warning:  Attempt to read property "post_type" on null in /wp-includes/theme.php on line 3757

On the second website (recruitment-agency.london), the frontend gives:

        Fatal error: Uncaught Error: Attempt to assign property "post_content" on null
    in /wp-admin/includes/post.php on line 748

    Call stack:

    get_default_post_to_edit()
    wp-admin/post-new.php:66

And the error log gives:

        Got error '
    PHP message: PHP Fatal error:  Uncaught Error: Attempt to assign property "post_content" on null in /wp-admin/includes/post.php:748\n
    Stack trace:\n#0 /wp-admin/post-new.php(66): get_default_post_to_edit('page', true)\n#1 {main}\n  thrown in /wp-admin/includes/post.php on line 748'

I have done the following:

1- Cleared the cache on server and browser

2- Tried with 2020 theme with no plugins active.

3- Repaired and optimised the database tables.

4- Reinstalled wordpress the latest version.

5- Contatced my hosting support and they had no idea.

Can anyone give me a hint please?

Update: the php code to remove the not optimised pages is here:

        <?php
    // Read ral-opt-slugs.txt file and store slugs in array
    $slugs = file('ral-opt-slugs.txt', FILE_IGNORE_NEW_LINES);

    // Connect to database
    $servername = "localhost";
    $username = "root";
    $password = "";
    $dbname = "test";

    $conn = mysqli_connect($servername, $username, $password, $dbname);

    // Check connection
    if (!$conn) {
        die("Connection failed: " . mysqli_connect_error());
    }

    // Ping the MySQL server to ensure the connection is still alive
    if (!mysqli_ping($conn)) {
        die("Connection lost.");
    }

    // Delete pages that are not in the list of slugs and not reserved
    $sql = "SELECT * FROM wp_posts WHERE post_type = 'page' AND post_name NOT IN ('" . implode("', '", $slugs) . "') AND post_name NOT LIKE 'media%' AND post_name NOT LIKE 'plugins%' AND post_name NOT LIKE 'themes%'";
    $result = mysqli_query($conn, $sql);
    if (mysqli_num_rows($result) > 0) {
        while ($row = mysqli_fetch_assoc($result)) {
            $id = $row['ID'];
            $sql = "DELETE FROM wp_postmeta WHERE post_id = '$id'";
            mysqli_query($conn, $sql);
            $sql = "DELETE FROM wp_posts WHERE ID = '$id'";
            mysqli_query($conn, $sql);
            echo "Deleted page with slug: " . $row['post_name'] . "\n";
        }
    } else {
        echo "No pages found for deletion.\n";
    }

    // Close database connection
    mysqli_close($conn);
    ?>

Regards

Answer 1

Thanks to _LS for the hint,

In fact, there were many rows with the same ID , i had to create new table , copy the old table rows with auto increment option, remove the old table then rename the new table to the old table's name. that did the trick.

Thanks all