Hi Vini,
Thank you so much for experienced and detailed answer 
yes,i have verified all the entries and methods which you suggested.
I have encountered such issues in my previous project.
I have maintaine the entires as you mentioned initially.
I have found the error in the outbound queue in SRM.
short dump updated in the backend system. then i found the error as below.
The current application triggered a termination with
Technical information about the message:
Message class....... "C_"
Number.............. 050
Variable 1.......... "No External System (such as CRM) Connected"
"MESSAGE_TYPE_X" " "
"SAPLCRM0" or "LCRM0U68"
"CRM_FIRST_CALL_OPERATIONS"
short dump updated in the backend system.
Can you tell me the significance of SMOGGEN?
I have another issue,
In another system,when i try to replicate the product category, some times,able to replciate the product category.
sometimes it is not working.
i couldl not find any outbound queue generation also in SRM.
can you explain me how to verify whether filters updated properly to load the requested data?
Many thanks.