[otrs] 3nd Subque Leve lost

Hi all, We currently have the problem that we do not see 3rd layer queues in the Queue View anymore. For example: |- Queue A -| |+ Queue B |- Queue C -| |+ Queue E |+ Queue F |+ Queue D We dont see Queue E and F. If i do change the Name of Queue C I also dont see E & F in the Admin -> Queue Section. Want went wrong ? How do i fix it ? Thanks