How to fix the outlook error 500 issue?

Question

UTC Date: [PII: Removed]
Client Id: [PII: Removed]
Session Id:[PII: Removed]
Client Version: [PII: Removed]
BootResult: accessDenied
Back Filled Errors: Unhandled Rejection: Error: 500:undefined|undefined:undefined
err: Microsoft.Exchange.Clients.Owa2.Server.Core.OwaExplicitLogonException
esrc: StartupData
et: ServerError
estack: Error: 500
   [PII: Removed]
st: 500
[PII: Removed]

Answer 1

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Hi Puman Lai •

I’m sorry you’re running into this — I understand you’re seeing “Error 500” in Outlook on the web, and the diagnostic details mention BootResult: accessDenied, ErrorExplicitLogonAccessDenied, and OwaExplicitLogonException. 

To help narrow down the cause and point you to the right fix, could you please share these details? 

1) Which mailbox are you trying to access? Are you signing in to your own mailbox, or trying to open another mailbox (for example: shared mailbox, group mailbox, or using “Open another mailbox”)? 

2) What is the exact web address (URL) where the error occurs? 

• Please copy/paste the full URL (or at least confirm which one it is): 
  • Personal Outlook.com: https://outlook.live.com/ or https://outlook.com/ 
  • Work/school Outlook on the web: https://outlook.office.com/ 

I’ll be glad to assist further once I have those two details. Wishing you a lovely day!

Answer 2

The error details show an HTTP 500 server error coming from Outlook on the web (OWA) with OwaExplicitLogonException and ErrorExplicitLogonAccessDenied. In the provided context, HTTP 500 issues in Exchange/OWA are addressed in two main ways, depending on where the failure occurs.

For Outlook on the web / ECP after Exchange updates:

1. If HTTP 500 appears after installing a cumulative update (CU) or security update on Exchange, reinstall the security update from an elevated command prompt:
   • Open Command Prompt as administrator.
   • Run the .msp file for the Exchange security update by typing its full path and pressing Enter.
   • Restart the Exchange server after the update completes.
2. If Outlook on the web or ECP still shows HTTP 500 errors such as “Could not load file or assembly Microsoft.Exchange.Common…”, follow the full guidance in the Exchange update troubleshooting article referenced in the context.

For HTTP 500 in OWA after upgrading Exchange 2013 to CU11 or later:

1. Stop IIS to release file locks:

      iisreset /stop
   

2. Move the folder C:\Program Files\Microsoft\Exchange Server\V15\Bin\Setup to a location outside the Exchange installation path (for example, C:\TEMP\Setup).
3. Back up SharedWebConfig.config from both:
   • C:\Program Files\Microsoft\Exchange Server\V15\ClientAccess
   • C:\Program Files\Microsoft\Exchange Server\V15\FrontEnd\HttpProxy
4. Open an elevated Command Prompt and change to the Exchange bin directory:

      cd %ExchangeInstallPath%\bin
   

5. Rebuild SharedWebConfig.config for ClientAccess:

      DependentAssemblyGenerator.exe -exchangePath "%ExchangeInstallPath%\bin" -exchangePath "%ExchangeInstallPath%\ClientAccess" -configFile "%ExchangeInstallPath%\ClientAccess\SharedWebConfig.config"
   

6. Rebuild SharedWebConfig.config for HttpProxy:

      DependentAssemblyGenerator.exe -exchangePath "%ExchangeInstallPath%\bin" -exchangePath "%ExchangeInstallPath%\FrontEnd\HttpProxy" -configFile "%ExchangeInstallPath%\FrontEnd\HttpProxy\SharedWebConfig.config"
   

7. Restart IIS:

      iisreset /start
   

If the HTTP 500 error started immediately after an Exchange CU/SU or version upgrade, apply the corresponding set of steps above on the Exchange server that hosts Outlook on the web.

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References:

• Fix failed Exchange Server updates
• Error in Outlook Web App after an upgrade to Exchange Server 2013 CU 11 or later: Your request cannot be completed right now