Hi there @Graubikeshop!
Don here from Shopify.
Thanks for that screenshot and the link to your store.
Could you let us know the name of this theme as you originally downloaded it so we can check on how you can get support for this theme?
Once we know that we can determine how and where you will be able to get further help on this.
Hi again @Graubikeshop!
Don from Shopify once again.
Thanks for letting me know that.
If you're using a version of a theme that is no longer supported by its developers, it will be a bit harder for you to get support on this.
You would always have the option of having a Shopify Expert take a look at troubleshooting this for you.
Long term, you might need to think about moving onto a theme that is supported, which you will be able to find here on our theme store.
The free themes there are supported by us here at Shopify while the paid themes are supported by their developers.
This may not be ideal for your situation, but we like to provide as many options as possible here.
Hopefully, another member of our community will have some knowledge to share on your current query from their own experience.
All the best!