Exchange Server 2016 install Certificate error

Fresh install of Win Server 2016 Standard
Updated AD & Schema for exchange install.  AD is on windows server 2008r2 box
Active Exchange server 2010 on win2008r2 box.  
Trying to set up Exchange 2016 and move everything over.

Step 7 of 13 Mailbox role Client Access Service.

Get the following 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: "Microsoft.Exchange.Management.SystemConfigurationTasks.AddAccessRuleCryptographicException: Could not grant Network Service access to the certificate with thumbprint 6240AA851641E061445586358AF5F38247B54B97 because a cryptographic exception was thrown. ---> System.Security.Cryptography.CryptographicException: Access is denied.

   at Microsoft.Exchange.Security.Cryptography.X509Certificates.TlsCertificateInfo.CAPIAddAccessRule(X509Certificate2 certificate, AccessRule rule)
   at Microsoft.Exchange.Security.Cryptography.X509Certificates.TlsCertificateInfo.AddAccessRule(X509Certificate2 certificate, AccessRule rule)
   at Microsoft.Exchange.Management.SystemConfigurationTasks.ManageExchangeCertificate.EnableForServices(X509Certificate2 cert, AllowedServices services, String websiteName, Boolean requireSsl, ITopologyConfigurationSession dataSession, Server server, List`1 warningList, Boolean allowConfirmation, Boolean forceNetworkService)
   --- End of inner exception stack trace ---
   at Microsoft.Exchange.Configuration.Tasks.Task.ThrowError(Exception exception, ErrorCategory errorCategory, Object target, String helpUrl)
   at Microsoft.Exchange.Configuration.Tasks.Task.WriteError(Exception exception, ErrorCategory category, Object target)
   at Microsoft.Exchange.Management.SystemConfigurationTasks.InstallExchangeCertificate.EnableForServices(X509Certificate2 cert, AllowedServices services)
   at Microsoft.Exchange.Management.SystemConfigurationTasks.InstallExchangeCertificate.InternalProcessRecord()
   at Microsoft.Exchange.Configuration.Tasks.Task.<ProcessRecord>b__b()
   at Microsoft.Exchange.Configuration.Tasks.Task.InvokeRetryableFunc(String funcName, Action func, Boolean terminatePipelineIfFailed)".