Cannot insert an image to a product

I cannot add anymore images to a product or upload new images. I am using version 2.3.0.2

Thanks

Maybe you're out of space?

Thank you for your quick reply but the problem is not a disk space problem, i will attach a screenshot of the error that i get, once i receive the window to select a picture or upload a new one:
- when i click on an existing picture it will show it on the full screen instead of selecting it as the product image
- when i click on the upload button nothing happens
- when i click on one of my images folders it shows a new page with no formating at all