A CAS user account is locked out when you use the New-TestCasConnectivityUser.PS1 script to create test mailboxes

When you use the New-TestCasConnectivityUser.PS1 script to create test mailboxes for OWA, ActiveSync, and Exchange Web Services connectivity monitoring, the CAS user account that is created by running the script is locked out (depending on your Group Policy settings) after multiple invalid logon attempts by the Default Application Pool on the Microsoft Exchange server that hosts the RPC and RPC with Certs virtual directory.

You may also see invalid logon events in the security log that resemble the following:

Audit Failure 3/30/2010 5:45:10 PM Microsoft Windows security auditing. 4625 Logon

An account failed to log on.

Subject:

Logon Type: 8

Account For Which Logon Failed:
Failure Information:
Process Information:
Network Information:
Detailed Authentication Information:

By default, ASP.NET impersonation is not enabled on the RPC and RPC with Certs virtual directories for Exchange Server. This behavior is by design.

This issue is resolved in Exchange Server 2010 Service Pack 1. For information about how to obtain Service Pack 1 for Exchange Server 2010, go to the following Microsoft Download Center website:�

In addition to the Test-CASConnectivityUser.PS1 script, you can use the Exchange Remote Connectivity Analyzer (ExRCA). To use ExRCA, go to the following Microsoft website:For more information about the Exchange Remote Connectivity Analyzer, go to the following Microsoft TechNet website: