Retrieve Identities by using query params

Summary

There is an issue while Retrieving Identities by using query params

Content

Hi,

I'm using /bpm/api/4.0/identities and passing query parameters as found here : https://docs.oracle.com/en/cloud/paas/process-cloud/cprrb/op-identities-get.html

All params are working except firstname,lastname & email.

It returns this : 

{"type":"https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.1","title":"Error in Identity Service.","status":"500","detail":"Error occurs while using Identity Service   Fix: Check underlying exception and correct the error. If the error persists, contact Oracle Support Services.","instance":"https://***************.integration.ocp.oraclecloud.com:443/bpm/api/4.0/identities?firstname=Ahmed","o:errorCode":"70647","o:errorDetails":[]}