In bone creation mode, there is already a joint in the place you want to create, so you can't click it to put a new one.
Page update date :
Page creation date :
To resolve this issue:
As an example, suppose the bottom bone is selected, and you want to create a bone that exactly follows the red circle. However, if you click there, the upper bone will be selected and you will not be able to create it well. So the first thing to do is to create it around it. However, keep the mouse clicked and held at this time.
Drag the newly created joint to the point where it overlaps the upper bone. That's it, you're done!