Background: Windows Challenge/Response (NTLM) is the authentication protocol used on networks that include systems running the Windows operating system and on stand-alone systems.
The Microsoft Kerberos security package adds greater security than NTLM to systems on a network. Although Microsoft Kerberos is the protocol of choice, NTLM is still supported.
When working with Outlook Web Access 2013 with NTLM authentication in the Mobile Access Portal, one of the requests fails to authenticate due to Pinger process authentication logic, which causes an authentication popup while using OWA.