Problem with remote script

Hi,

Our remote helpdesk team need to run Exchange 2010 script. We've prepared procedure which contains:
- start Windows PowerShell
- $UserCredential = Get-Credential
- $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUrihttp://<FQDNof Exchange 2010 server>/PowerShell/ -Authentication Kerberos -Credential $UserCredential

Durin last line there is an error message:
Connecting to remote server failed with the following error message : WinRM cannot process the request. The following error occured while using Kerberos authentication: The network path was not found.
Possible causes areuser name or password,Kerberos, Kerberos accepts domain,Service Principal Name (SPN) for the remote computer name and port doesnot exist., etc.
Tested user is member of sec. group "View-Only organization management".

Do you have advice how to resolve it and connect to the Exchange Server remotely via powershell?

Thnx