network policy server discarded the request for a user

Log Name:      Security
Source:        Microsoft-Windows-Security-Auditing
Date:          4/29/2014 4:17:14 PM
Event ID:      6274
Task Category: Network Policy Server
Level:         Information
Keywords:      Audit Failure
User:          N/A
Computer:      WIN-GB2JFFWVK4S.cisco
Description:
Network Policy Server discarded the request for a user.

Contact the Network Policy Server administrator for more information.

User:
Security ID: NULL SID
Account Name: hojati
Account Domain:CISCO
Fully Qualified Account Name:CISCO\hojati

Client Machine:
Security ID: NULL SID
Account Name: -
Fully Qualified Account Name:-
OS-Version: -
Called Station Identifier:acf1dff1bb3d
Calling Station Identifier:00225f74ec36

NAS:
NAS IPv4 Address:10.13.13.6
NAS IPv6 Address:-
NAS Identifier:acf1dff1bb3d
NAS Port-Type:Wireless - IEEE 802.11 
NAS Port: 130

RADIUS Client:
Client Friendly Name:AP
Client IP Address:10.13.13.6

Authentication Details:
Proxy Policy Name:Secure Connection
Network Policy Name:-
Authentication Provider:Windows 
Authentication Server:WIN-GB2JFFWVK4S.cisco
Authentication Type:-
EAP Type: -
Account Session Identifier:-
Reason Code: 1
Reason: An internal error occurred. Check the system event log for additional information. 

Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Microsoft-Windows-Security-Auditing" Guid="{54849625-5478-4994-a5ba-3e3b0328c30d}" />
    <EventID>6274</EventID>
    <Version>0</Version>
    <Level>0</Level>
    <Task>12552</Task>
    <Opcode>0</Opcode>
    <Keywords>0x8010000000000000</Keywords>
    <TimeCreated SystemTime="2014-04-29T11:47:14.612Z" />
    <EventRecordID>3847</EventRecordID>
    <Correlation />
    <Execution ProcessID="604" ThreadID="3036" />
    <Channel>Security</Channel>
    <Computer>WIN-GB2JFFWVK4S.cisco</Computer>
    <Security />
  </System>
  <EventData>
    <Data Name="SubjectUserSid">S-1-0-0</Data>
    <Data Name="SubjectUserName">hojati</Data>
    <Data Name="SubjectDomainName">CISCO</Data>
    <Data Name="FullyQualifiedSubjectUserName">CISCO\hojati</Data>
    <Data Name="SubjectMachineSID">S-1-0-0</Data>
    <Data Name="SubjectMachineName">-</Data>
    <Data Name="FullyQualifiedSubjectMachineName">-</Data>
    <Data Name="MachineInventory">-</Data>
    <Data Name="CalledStationID">acf1dff1bb3d</Data>
    <Data Name="CallingStationID">00225f74ec36</Data>
    <Data Name="NASIPv4Address">10.13.13.6</Data>
    <Data Name="NASIPv6Address">-</Data>
    <Data Name="NASIdentifier">acf1dff1bb3d</Data>
    <Data Name="NASPortType">Wireless - IEEE 802.11 </Data>
    <Data Name="NASPort">130</Data>
    <Data Name="ClientName">AP</Data>
    <Data Name="ClientIPAddress">10.13.13.6</Data>
    <Data Name="ProxyPolicyName">Secure Connection</Data>
    <Data Name="NetworkPolicyName">-</Data>
    <Data Name="AuthenticationProvider">Windows </Data>
    <Data Name="AuthenticationServer">WIN-GB2JFFWVK4S.cisco</Data>
    <Data Name="AuthenticationType">-</Data>
    <Data Name="EAPType">-</Data>
    <Data Name="AccountSessionIdentifier">-</Data>
    <Data Name="ReasonCode">1</Data>
    <Data Name="Reason">An internal error occurred. Check the system event log for additional information. </Data>
  </EventData>
</Event>