error Could not grant Network Service access to the certificate with thumbprint

Hello,

I cant find my solution that woks.

I have a fresh install of windows 2012R2 server.

I was installing exchange 2013 R1 on the server and i got the 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 9A9744EF8A9251AF974C6D8C25466D602D08B82C because a cryptographic exception was thrown.".

I think the error has to do with a certicate??

I dont know.

Greetings,

Albert Koenders