Trying to find a source of the Invalid Login attempts

I have a server windows 2k8 that has port 3389 open for the persons that need RDP to run an application while away from the office.
I have all logging for successful and failed logins going on.
I am getting thousands of failed logins within a 24hr period.

Here is the problem these thousands of logins that are failing are showing up in the event logs as an error 4625 but within the log entry there is only a "-" where a source ip address should be and a "-" where a source port should be.

I can try to login to the server using "bad credentials" and the source ip address and port show up for this type of  failed login.

example of event log below.
An account failed to log on.

Subject:
      Security ID:            NULL SID
      Account Name:            -
      Account Domain:            -
      Logon ID:            0x0

Logon Type:                  3

Account For Which Logon Failed:
      Security ID:            NULL SID
      Account Name:            jose
      Account Domain:            

Failure Information:
      Failure Reason:            Unknown user name or bad password.
      Status:                  0xc000006d
      Sub Status:            0xc0000064

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

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

Detailed Authentication Information:
      Logon Process:            NtLmSsp
      Authentication Package:      NTLM
      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.

Please advise why this may not be showing the source ip address and port.