Exchange Server 2013 installation error at Step 10/15

I try to install Exchange Server 2013 on a fresh install of Windows Server 2012.

Windows Server 2012, have already install on it:

• AD CD
• DNS
• IIS
• Exchange 2013 Prerequisites for Win.Server 2012 like described here http://technet.microsoft.com/en-us/library/bb691354(v=exchg.150).aspx

And the (winner) error message is:

Exchange Server component Mailbox role: Client Access service failed.
Error: Error:
The following error was generated when "$error.Clear();
         
Install-ExchangeCertificate -WebSiteName "Exchange Back End" -services "IIS, POP, IMAP" -DomainController $RoleDomainController -InstallInTrustedRootCAIfSelfSigned $true
          if ($RoleIsDatacenter -ne $true -And $RoleIsPartnerHosted -ne $true)
          {
            Install-AuthCertificate -DomainController $RoleDomainController
          }
        " was run: "Could not grant Network Service access to the certificate with thumbprint ABC7C6378BF63CED166794CFBF410C73B29EDD3A because a cryptographic exception was thrown.".

I search online for a solution and I found many others with same problem but any solution yet. :(
If anyone can help me I am able to dedicate him my next ode.

Thank you,
Adrian