The mixed content fixer could not be detected due to a cURL error: cURL error 60: Peer’s Certificate issuer is not recognized. . cURL errors are often caused by an outdated version of PHP or cURL and don’t affect the front-end of your site. Contact your hosting provider for a fix.
This issue is caused by the fact that our servers don’t provide a so-called CA Chain with the SSL certificate. Some tools and devices require this in order to verify the legitimacy of an SSL certificate. This feature is not available on free hosting. If you need it, you may want to upgrade to premium hosting instead.
There may also be a workaround for you which doesn’t require you to pay anything. But in that case, it would help a lot if you could tell more about what exactly shows that error message.