As in the title. This was working perfectly fine yesterday. Absolutely no changes where made to the server.
What I noticed, is thumbnails are generated in the thumbnail cache folder, just not being served online. Image preview doesn't work either. However, opening image in new tab works fine.
Running on ubuntu server +mariadb +apache2
tested with images uploaded via web browser and via moving them into home directory directly on the back end.
Customer support service by UserEcho