Hello,
first of all, thanks for your help!
And next time I will use the general German support 😀
Exactly, I use WooCommerce.
I already asked in the WooCommerce forum but someone explained the following to me:
Image uploads and the Media Library are handled by WordPress core, not WooCommerce. Since uploads are failing and images are not visible or selectable across the site, the issue is likely related to WordPress or the server environment rather than WooCommerce itself.
https://share.icloud.com/photos/08dzxhGdXuckz6C_1OU11pGeA