Exchange 2007 OWA Error after installing Service Pack 3 (MSExchange OWA event 65)

Hi everyone, I have multiple servers in Exchange 2007 SP1, Windows Server 2003 SP2 64bit.

I installed SP3 and RU15 a CAS / HUB server and now I access OWA, showing the below error:

-------------------------------------
Outlook Web Access did not initialize. There has been an event for the system administrator can resolve the problem. Contact the support of the organization.
Object reference not set to an instance of an object.


Request
URL: https: // mailserver01: 443 / owa / auth / error.aspx url = https: // mailserver01 / owa / & reason = 0

Exception
Exception type: Microsoft.Exchange.Clients.Owa.Core.OwaInvalidConfigurationException
Exception message: Object reference not set to an instance of an object.

Call stack
in Microsoft.Exchange.Clients.Owa.Core.OwaConfigurationManager.CreateAndLoadConfigurationManager () in Microsoft.Exchange.Clients.Owa.Core.Globals.InitializeApplication () in Microsoft.Exchange.Clients.Owa.Core.Global.ExecuteApplicationStart (Object sender, EventArgs e)

Inner Exception
Exception type: System.NullReferenceException
Exception message: Object reference not set to an instance of an object.

Call stack
in Microsoft.Exchange.Clients.Owa.Core.Configuration.CheckPublicFolders (ADSystemConfigurationSession session, ADObjectID [] pfdbIds, Boolean & allLegacy, Boolean & allLater) in Microsoft.Exchange.Clients.Owa.Core.Configuration..ctor (ADSystemConfigurationSession session, String virtualDirectory , String WebSiteName, ADObjectID distinguishedName, Boolean isPhoneticSupportEnabled) in Microsoft.Exchange.Clients.Owa.Core.OwaConfigurationManager.LoadConfiguration () in Microsoft.Exchange.Clients.Owa.Core.OwaConfigurationManager.CreateAndLoadConfigurationManager ()

-------------------------------------


In server events next event is logged

----------------------------------------------
Event Type: Error
Event Source: MSExchange OWA
Event Category: ADNotifications
Event ID:. 65
Date: 12/27/2014
Time: 7:20:54
User: Not available
Team: mailserver01
Description:
There was an error loading the configuration parameters of Outlook Web Access. Virtual directory "owa". Website: "Default Web Site".
Error message:
"Object reference not set to an instance of an object."
----------------------------------------------


HOW CAN I SOLVE THIS?

thank you very much

---

Microsoft Certified IT Professional Server Administrator