Automatic renewal of certificates through CEP / CES.

We currently have a PKI on Windows 2008 R2 and in this case as customers use notebooks with Windows 7 SP1.
I have problem with the automatic renewal of computer certificate through CEP / CES.
Services CEP / CES are installed on the same server, the CA is in another server.
You want to automatically renew computer certificate through Internet.

These services are configured to only computer certificate renewal and renovation to allow authentication using a certificate previously issued to PC.
The first computer certificate is issued automatically through the settings in Group Policy in Active Directory, then the team has its certificate is configured PC Local Group Policy to configure the server URL CEP / CES.

I have no problem when I do the renewal through the MMC, only occurs when the team wants it done automatically.

Error events are:
-
Event ID 68
Certificate enrollment for Local system failed in authentication to policy servers with ID  {6ADBCC41-F91F-405C-88EC-4FEF12CF7FCF} 
(Provider could not perform the action since the context was acquired as silent. 0x80090022 (-2146893790))

Event ID 67
Certificate enrollment for Local system failed to load policy from policy servers with ID  {6ADBCC41-F91F-405C-88EC-4FEF12CF7FCF} 
(Provider could not perform the action since the context was acquired as silent. 0x80090022 (-2146893790))

Event ID 6
Automatic Certificate enrollment for Local system failed (0x80090022) Provider could not perform the action since the context was acquired as silent.
-

The documentation used to install CEP / CES is:
http://www.microsoft.com/en-us/download/details.aspx?id=1746

I thank anyone who can guide me with this problem.
Greetings.