Custom fonts loading in http – "Unsecure scripts" error message in chrome

Hey!

I have a problem with my custom fonts I uploaded to my website. I want to use the google font “Montserrat”, it worked in my browsers Firefox and Chrome. But in Chrome I noticed an error message right next to the URL field. The website wants to load scripts from unauthenticated sources. I opened the JS console in Chrome, then I find out, the fonts are loaded via http, not https.

There are many log entries like this:

Mixed Content: The page at ‘https://www.ryoshi.de/’ was loaded over HTTPS, but requested an insecure font ‘http://www.ryoshi.de/wp-content/uploads/avia_fonts/type_fonts/montserrat/montserrat-black.ttf’. This request has been blocked; the content must be served over HTTPS.
(anonymous) @ mediaelement-and-player.min.js?ver=4.2.6-78496d1:12
25.2 @ mediaelement-and-player.min.js?ver=4.2.6-78496d1:12
i @ mediaelement-and-player.min.js?ver=4.2.6-78496d1:12
(anonymous) @ mediaelement-and-player.min.js?ver=4.2.6-78496d1:12
6.2 @ mediaelement-and-player.min.js?ver=4.2.6-78496d1:12
i @ mediaelement-and-player.min.js?ver=4.2.6-78496d1:12
e @ mediaelement-and-player.min.js?ver=4.2.6-78496d1:12
(anonymous) @ mediaelement-and-player.min.js?ver=4.2.6-78496d1:12

What can I do about this? I am using the plugin “Really simple SSL” and activated the mixed content filter (not now, quite for a while now), this shouldn’t happen at all.

Thanks for your help in advance,
best regards