Hi, was about to report this but you guys spotted it earlier :)
Anyway, I think this is an issue with your SSL certificate and clearing cache may not fully resolve it. Your cert is only meant for "steemleo.com" while some of the users (including me) probably bookmarked the site as "www.steemleo.com". As a result, when we access "www.steemleo.com" we will hit the cert error. You might want to check with your certificate vendor on how to resolve this. Typically, the "www" subdomain should be included as a SAN (subject alternative name) which will prevent this altogether.
Previously, the SSL was only for steemleo.com as well, it was just www was being redirected to steemleo.com.
I see. Thanks for the explanation!