Error when searching for entries in secure store

Hi All,

I need to assign the certificate in the sender agreement for signature verification and decrpting. So when i search for entries, i am getting the error as " Error when searching for entries in Secure Store".

Details of the Error is showing as:

Service call exception; nested exception is: com.sap.engine.services.webservices.jaxrpc.exceptions.InvalidResponseCodeException: Invalid Response Code: (401) Unauthorized.

What is the reason for the above error and how to rectify it..?

Suggest some useful solution

Regards

Prakash