The seemingly related question offered not much help except for the first answer saying it could be Nonce related, but it doesn’t help in finding out how…? (neither do I understand the documentation).

The issue started after I changed my settings page to a Tabs-based page.

Although I get the “Settings saved.” alert when the page is posted but nothing gets written to the DB.

When I use the following bit of code to check for the $input that is passed to the sanitize_callback function:-

function my_sanitize ( $input ) {                   // prfx_sanitize_options( $input ) {
        $options = get_option('my_setting_section');
        
        $newinput = array();

        ob_start();                    // start buffer capture
        var_dump( $input );           // dump the values
        $contents = ob_get_contents(); // put the buffer into a variable
        ob_end_clean();                // end capture
        error_log($contents);

NULL is printed in the error_logs.

• If it is nonce related, how do I check it?
• Where else can I look for problems?

Thank you!