Hi Gabe,
thanks for the hint! The answer to this problem was a missing <?php wp_footer(); ?> in footer.php of the theme.
Thank you very much!
Hi again,
I also checked the jquery versions at my page, but there’s only the jquery version from Search Autocomplete plugin and the standard jquery from wordpress.
I also tested the Search Field Selectors [name=s] , [name=#s] and #s , but same issue.
I appreciate your support.