Failed when request a cert.0x800706ba

Question

Your request failed. An error occurred while the server was processing your request.

Contact your administrator for further assistance.

Request Mode:
newreq - New Request
Disposition:
(never set)
Disposition message:
(none)
Result:
The RPC server is unavailable. 0x800706ba (WIN32: 1722 RPC_S_SERVER_UNAVAILABLE)
COM Error Info:
CCertRequest::Submit: The RPC server is unavailable. 0x800706ba (WIN32: 1722 RPC_S_SERVER_UNAVAILABLE)
LastStatus:
The RPC server is unavailable. 0x800706ba (WIN32: 1722 RPC_S_SERVER_UNAVAILABLE)
Suggested Cause:
This error can occur if the Certification Authority Service has not been started.