Error with Start Planning CTM

Hi I am getting following error in CTM transaction after triggering start planning.

" No free slot could be found on any of the destination addresses". Upon debugging the same I found error has been raised in following code

TRY.

      lo_eng_parameter = lo_engine->execute( iv_dest_id       =      

                                             iv_msg_loghandle = iv_loghandle ).

    CATCH cx_rccf_engine INTO lo_ex_engine.

      lv_msg = lo_ex_engine->get_text( ).

      MESSAGE lv_msg TYPE 'E'.

  ENDTRY.

PLease share if u have any idea.