I have a bug in our site can u help us

admin.php?page=pmpro-membershiplevels&edit=45:56 Mixed Content: The page at ‘https://www.kademia.tn/wp-admin/admin.php?page=pmpro-membershiplevels&edit=45’ was loaded over HTTPS, but requested an insecure stylesheet ‘https://ajax.googleapis.com/ajax/libs/jqueryui/1.9.2/themes/smoothness/jquery-ui.css?ver=4.7.2’. This request has been blocked; the content must be served over HTTPS.

hello i found this bug in log console of my navigator when i try to enter to the list of levels the page refresh automatically … please how to fix that bug thanks