I also tried the / upfront, and copying the json file into virtually every folder, as well as using the whole path “http://192.168.2.45/test.json”.
That all did not work, as I just found the bug: there is a comma missing after the dataloader dict definition. 😉
F12 in chromium-browser and then console and clicking the error message leaded me to the line which was faulty, after which I found the bug.
Now suddenly ALL paths I tried before seem to work. Haha.
Thanks for the help. I learned something today, again. 🙂