Hi Suraj,
Issue was related to missing Reference document categories PPO & VAS in inbound delivery reference document type profile
SPRO - EWM - Cross Process Settings - Delivery processing - Reference Documents - Define Reference Document Type Profile
I have assgined Reference document categories PPO & VAS in below inbound delivery reference document type profiles
/SCWM/INB_REQ_KTS
/SCWM/INB_PRD_KTS_KTR
/SCWM/INB_REQ_DLV_KTS
/SCWM/INB_PRD_DLV_KTS_KTR
With best regards
Shankarling