Are you starting on a fresh world? Mapgen won’t generate the new locations on an existing one.
To check if mapgen could even find the location, open debug menu (needs to be bound in keybindings first), then map editor, then mapgen (I think it’s ‘o’) and find the new location. If it isn’t there, it means it isn’t visible to mapgen and thus won’t be generated.
If it’s visible to mapgen and still won’t generate on new maps, it may have too restrictive settings. There is no warning if that happens, it will simply not spawn anywhere.