I am getting a Runtime Error when I search the Alias in Mobile Admin. It does not matter which account I am searching. Source Error: An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below. Stack Trace: [NullReferenceException: Object reference not set to an instance of an object.] Microsoft.Exchange.AirSync.Admin.Mailbox.propFindRequest(String deviceUri) +391 Microsoft.Exchange.AirSync.Admin.Mailbox.getDevices() +194 Microsoft.Exchange.AirSync.Admin.Devices.refreshDevicesTable() +138 Microsoft.Exchange.AirSync.Admin.Devices.Page_Load(Object sender, EventArgs e) +190 System.Web.UI.Control.OnLoad(EventArgs e) +67 System.Web.UI.Control.LoadRecursive() +35 System.Web.UI.Page.ProcessRequestMain() +750

Please try the steps below to troubleshoot this issue: Created a host file on the Exchange server with the netbios name of the Exchange server and then try again;Ran the below mentioned command to delete SetHostName and then try again cscript adsutil.vbs delete w3svc/1/SetHostName hope it is helpful. Fiona Liao TechNet Community Support