I was going to enter this into the knowledge base and found that there are plenty of articles about PNAgent authentication troubleshooting. This information describes the authentication process for PN Agent. A better understanding of the authentication process can better assist you in troubleshooting an issue. 

Pass-Through authentication for PN Agent can operate in Kerberos and non-Kerberos mode.

  • In non-Kerberos mode, the credentials used to login to the desktop OS are captured and replayed by (SSONSVR.exe) or HTTP communication between PNA client and PNA web site, and between PNA web site and XA XML service.
  • In Kerberos – mode, HTTP communication between PNA client and the PNA web site uses Integrated Windows Authentication (IWA).
  • Internet Explorer configuration (such as security zone settings) can affect the behavior of PNA Pass-Through authentication