Exchange issues

Working with exchange 2010. I have clients that use both outlook 2011 and 2010. Today ran into a problem where user's are all being prompted for their password. The solution we have is to change their password via the OWA but then about an hour later, they get the prompt for password again and exchange does not like the password.

Anything with ---- is jut removing the info for privacy.

Log Name:      Security
Source:        Microsoft-Windows-Security-Auditing
Date:          3/16/2015 3:16:58 PM
Event ID:      4625
Task Category: Logon
Level:         Information
Keywords:      Audit Failure
User:          N/A
Computer:      ----
Description:
An account failed to log on.

Subject:
      Security ID:            SYSTEM
      Account Name:            ----
      Account Domain:            ----
      Logon ID:            0x3e7

Logon Type:                  8

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

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

Process Information:
      Caller Process ID:      0xdcc
      Caller Process Name:      C:\Windows\System32\inetsrv\w3wp.exe

Network Information:
      Workstation Name:      ----
      Source Network Address:      ----
      Source Port:            51244

Detailed Authentication Information:
      Logon Process:            Advapi  
      Authentication Package:      Negotiate
      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.

Any ideas?