Hi Dipak,
When event message to send to SAP EM, it checks event handler exists for that event message tracking id. If not exists then it will be in /SAPTRX/EVM_UNPR.
Take the tracking id of event message from /SAPTRX/EVM_HDR and check event handler presents in /SAPTRX/EH_HDR.
Check the configuration of SAP ECC EM in AOT -> Parameter Setup tab. i.e Refer standard tracking id extractor - PCM10_ITEM.
Regards
GGOPII