Custom Function Plugin

Hello,

I see the below error while executing the custom plugin function. I verified the connection and third-party credentials, and it all looks correct.

Could anyone please help me understand what the issue could be?

Error: (Expression evaluation error in rule 'cbg_po_eds_addmerchant' at function fn!cmpo_eds_ws_getbotwinstitution [line 3]: Unable to find a required instance of SecureCredentialsStore.) (Data Outputs)

Server Log: 

Snippet where it is failing: 

public static void main(String[] args) {

             ServiceContext sc = null;

             SecureCredentialsStore credentialStore = null;

             String authenticationKey = null;

             String serviceURL = "">">test:8080.asmx";  --> Dummy URL here

             CMPO_GetBoTWInstitution obj = new CMPO_GetBoTWInstitution();

             BWCMPOEDSDGConfigInstitution botwInstitute = obj

                          .CMPO_EDS_WS_GetBoTWInstitution(sc, credentialStore,

                                       authenticationKey, serviceURL, "TEST");

             System.out.println("BoTW Institutiion id is "

                          + botwInstitute.getInstitutionId());

Thank You.