Icons for Articles are not Generated in '/generated' directory


Hello everyone,

I have a problem with generating the images for Articles.
When I am adding images to the new or existing product, images are uploaded correctly to Admin-Backend and on the server as a Thumbnail, but are not generated in the:
So, if I try to open in the browser with right click, I am getting: 404 Not Found but the path is generated for the image.

Ex. For the product: Test 1, I added an image: test1.png in the admin backend.
The image exists on the server: /out/pictures/master/product/7/test.png

But, it is not generated and cannot be loaded in the front of the shop but this URL is generated if I try to open the image in a new tab: /out/pictures/generated/product/3/test.png

Thanks for your help!