Event ID 4625 - unknown username or bad password

The Security Log on my Exchange 2013 server is loaded up with Event ID 4625 Audit Failures. I get the following every couple seconds:

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: HealthMailbox538adf120d884da3a932f7bc3b22a320@**********.com

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: ::1

Source Port: 60354

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.

The account name is sometimes listed as "HealthMailbox" followed by a long string of characters @domain.com.  Other times there won't be anything listed for the Account name.  I can't figure out what is causing

March 20th, 2014 5:43pm

Hi,

You are getting this error message because health mailbox is unable to login to mailbox server. In exchange 2013 whenever Health Manager service restart. You can get rid of these alerts by removing all existing healthmailboxes by using the EMS command given below.

Get-Mailbox -Monitoring | Remove-Mailbox

...or if you only want to delete a single one:
Get-Mailbox "HealthMailboxec1ed3f5774d4f51ab89da8bfe99f888" -Monitoring | remove-mailbox

..and when done, you should restart MSExchangeHM. Because when you restart MSExchangeHM service it will create a new health mailbox for database.

Kindly mark this as answer if it fulfill your requirements. Thanks.

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March 20th, 2014 7:43pm

Thanks for the info Riaz!  That cleared up the the errors!
March 20th, 2014 8:02pm

Always welcome.
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April 2nd, 2015 12:58pm

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