RA Server Generating Several Event 4625 Entries Per Second

[silnocus 0]

I've been trying to figure out the source of this for a few days now, but haven't made any progress beyond "they stop when I stop EraServerSvc." Here's what these events look like:

An account failed to log on.

Subject:
	Security ID:		S-1-0-0
	Account Name:		-
	Account Domain:		-
	Logon ID:		0x0

Logon Type:			3

Account For Which Logon Failed:
	Security ID:		S-1-0-0
	Account Name:		
	Account Domain:		

Failure Information:
	Failure Reason:		An Error occured during Logon.
	Status:			0xC000006D
	Sub Status:		0x80090325

Process Information:
	Caller Process ID:	0x0
	Caller Process Name:	-

Network Information:
	Workstation Name:	-
	Source Network Address:	-
	Source Port:		-

Detailed Authentication Information:
	Logon Process:		Schannel
	Authentication Package:	Schannel
	Transited Services:	-
	Package Name (NTLM only):	-
	Key Length:		0

This event is generated when a logon request fails. It is generated on the computer where access was attempted.

The Subject fields indicate the account on the local system which requested the logon. This is most commonly a service such as the Server service, or a local process such as Winlogon.exe or Services.exe.

The Logon Type field indicates the kind of logon that was requested. The most common types are 2 (interactive) and 3 (network).

The Process Information fields indicate which account and process on the system requested the logon.

The Network Information fields indicate where a remote logon request originated. Workstation name is not always available and may be left blank in some cases.

The authentication information fields provide detailed information about this specific logon request.
	- Transited services indicate which intermediate services have participated in this logon request.
	- Package name indicates which sub-protocol was used among the NTLM protocols.
	- Key length indicates the length of the generated session key. This will be 0 if no session key was requested.

There are about 6 of these per second while the service is running. They stop immediately when I stop the service. Searching for the status and substatus codes doesn't seem to give me any relevant information, at least as far as I can tell.

Does anyone have any ideas what part of the RA service might be causing these?

[MartinK 376]

Logon process Schannel indicates that it is TLS related -> it will be triggered most probably by failing AGENT connections. Error code 0x80090325 (SEC_E_UNTRUSTED_ROOT) means "The certificate chain was issued by an authority that is not trusted." Are there any errors in SERVER's trace log indicating network or security issues? Mentioned error may be triggered by failed AGENT-to-SERVER connection due to missing CA certificate, but I am not sure what side of channel is missing it. Are there any AGENT that are possibly not connection because they are missing CA certificate to verify SERVER's TLS certificate?