It seems to be an issue due to Mixed content.

Your site is running on HTTPS whereas some URL are still calling assets via HTTP and that can be the cause.

You have an error in your console.

Mixed Content: The page at ‘https://gaertner.audio/’ was loaded over HTTPS, but requested an insecure script. This request has been blocked; the content must be served over HTTPS.

This might be the cause.

So please check this once and let me know if you need any assistance.

Thanks,
Kartik

I suggest reading CloudFlare documentation about this; first, learn about the SSL modes offered by CloudFlare, to check you are using the correct mode:

https://support.cloudflare.com/hc/en-us/articles/200170416-Understanding-Cloudflare-SSL-options

I guess you must be using Flexible SSL.

Then check this:

https://support.cloudflare.com/hc/en-us/articles/200170476-How-do-I-fix-the-SSL-Mixed-Content-Error-Message-

Hope this helps.