Thanks Keith for quick response.
Yes. My bad 
We don't have REST V2 deployed. Ours is SAP NW IDM 7.2 SP7.
From section 'Deploying the REST Interface Version' i could see prerequisite as SAP NetWeaver Identity Management Identity Center 7.2 SP8 so the document may not applicable for us.
I had a quick look at SAP NetWeaver Identity Management Identity Cent... | SCN and will check for any info available on XSRF token missing or authorization applicable for our environment.