Oh Synology NAS, I am not familiar with their and I haven't use it before. This happened in Windows in my experience. Thank you for the link! Now I remember th

Oh Synology NAS, I am not familiar with their and I haven't use it before. This happened in Windows in my experience. Thank you for the link! Now I remember there is one more step, I fixed it by putting the library in the root folder of the drive. That solved the issue for me. I only tried it for a day and shut it down. I am planning to get RPI and put calibre-web in it. It still in my todo list.