Site "%1" (%2) has the same site code as another site. Possible cause: Hierarchy Manager has detected that a child site has ...

%11Site "%1" (%2) has the same site code as another site.

Possible cause: Hierarchy Manager has detected that a child site has the same site code as this site or another child site.
Solution: Each site must have a unique site code. Deinstall the child site and reinstall it using a unique site code.%0