Custom query parameter not defined

Hello,

Thank you for contacting Rank Math and bringing your concern to our attention. I’m sorry for any inconvenience this issue may have caused you.

The error is because the Sitelinks Searchbox schema is not rendering special characters correctly.

To fix this, please try using this filter on your site:

add_filter( 'rank_math/json_ld/search_url', function( $url ) {
if ( 'de' === ICL_LANGUAGE_CODE ) {
return 'https://www.greatergood-leadership.com/?s={search_term_string}&lang=de';
}
return $url;
} );

The filter should be added to your active theme’s functions.php file. Here’s another way to apply the filter using the rankmath.php file:
https://rankmath.com/kb/filters-hooks-api-developer/#adding-filters-and-hooks-in-rank-math-php

Once done, clear your website’s cache and check again the URL using Google’s Rich Results test. If the issue is already fixed there, you can validate the error in your Google Search Console account.

Regarding your translated pages on SERPs, translation plugins like WPML add hreflang to the translated pages so Google can figure out that a particular page is a translated version of another page on your website.

I hope that helps.

Thank you.