Unable to Run Services using api Call when Thingworx is authenticated using SAML

In our enterprise we have an instance of Thingworx which is authenticated using SAML.

Previously we were using ADFS authentication, I tried creating an application key and run a service from a different application, i was able to but after this SAML authentication when I create an appKey and use it in the API to run a thingworx service I am not able to. It is giving me unauthorized 401 as response.

Can you say what I am missing in addition to appKey is there something I have to add in my request ?

Any thoughts on this would help me.. 

Thank you

Regards

Viswadeep V