Hello Jansi, thank you for response.
I do have have suggested authorization, i.e. SAP_TECHNICAL_ADMIN_COMP and The service/default_host/sap/bc/webdynpro/sap/wdc_itcal_main is activated.
The systems which are not refelecting in IT Calander are Either Stand alone Java systems like EIS or Bobj or either MDM or may be Live cache systems.
all of these have DAA installed in it and manage system config have been set properly.
Now how can I get those systems reflecting in IT Calender.