Hi Deepak,
If I directly using transaction SICF to test web service WDA_FCLM_BAM_HIERARCHY in S/4HANA, I will get the same error you faced.
But in normal situation, access this App from Fiori Launchpad (as you know, there should be one configured web dispatcher), I can see the main screen.
So let your consultants to test this App in FLP and check if everything is fine.
Regards,
Ning