Hello Faisal,
Please check the following in your system:
1. Check SICF services w.r.t enhancement set are active. Compare the services with other system which is working fine.
2. All custom developments have been generated correctly.
3. Ask basis to put a rfc, abap and db trace, while you trying to perform your activity. Trace may give you some clues.
4. Check if there are any short dumps in the system.
5. Make sure the SPRO customising setting w.r.t to enhancement set is correct.
I hope above helps.