jquery.min.js:2 Mixed Content: The page at 'https://www.domain.com/oc-admin/' was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint 'http://www.domain.com/oc-admin/index.php?page=ajax&action=check_themes'. This request has been blocked; the content must be served over HTTPS.

@joji
On what osclass version it was and how this can be reproduced? Does not look like it could be done at Osclass 4.4, but I might be wrong
...if in config.php is web url with https...