Can't create POI

I can't create a POI specifically on my Map anywhere in my world (doesn’t matter if it is inside an area, or not, and it doesn’t matter if it is close to another POI or not). It also dosen't matter if I clone the world or if I try creating a POI in an already existing campaign of that world. But I can create a POI in any other world.
I have noticed this problem for a week, and I have already tried it in a different web browser, but the results are always the same… nothing.