InvalidJson error when trying to use new Outlook

Question

I have tried multiple times the "Try the new Outlook" toggle in my current version of Microsoft Outlook and every time I do it I get an error before the application even fully starts once. Below is the text from the error dialog (which I had to copy applying OCR to a screenshot since it would not allow me to copy the text normally, and image uploading in this forum does not seem to work either).

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Something went wrong

We ran into an error - Error: InvalidJson

UTC Date: 2024-05-10T15:40:58.358Z

Client Id: F8BDE14B95C44DC6B6277BA17D1DA1FF

Session Id: fa6b2acd-c029-e748-8b44-7374ffd8b6ea

Client Version: 20240503010.21

Native Host Version: 1.2024.501.300

BootResult: network

err: Error: InvalidJson

esrc: StartupData

et: ServerError

estack: Error: InvalidJson at https://res.cdn.office.net/owamail/hashed-v1/scripts/owa.native.894748e8.js:3:49056

backfilledErrors: Back Filled Errors: Unhandled Rejection: TypeError: Failed to fetch:undefined|Unhandled Rejection: Error: InvalidJson:undefined|undefined:undefinedlundefined:undefined

The new Outlook could not successfully launch. Try 'Troubleshoot', or please try again later.

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Neither "Retry" or "Troubleshoot" are of any help.

Answer 1

Dear Javier Dehesa,

Thank you for reaching out to Microsoft Community. I'm sorry to hear that you're experiencing an error when trying to use the new Outlook. The error message you're seeing suggests that there may be an issue with the JSON data being sent or received by the application.

To troubleshoot this issue, I would recommend trying the following steps:

1. Microsoft Office Repair:
   • Open Settings by clicking on the Start menu and selecting the gear icon.
   • Choose Apps from the options and then select Installed Apps.
   • Scroll down the list of apps and find Microsoft Office.
   • Click on Microsoft Office, then select Advanced options.
   • Choose Repair or Online Repair.
   • Once the repair process is complete, restart your computer to ensure the changes take effect.
2. Remove the Work or School Account:
   • Go to the Settings window.
   • Select Accounts.
   • Choose Access work or school.
   • This should show a window where you can select the account and choose Disconnect.
   • Once Disconnected, restart your computer and check the issue again.
3. Delete the Existing Outlook Profile:
   • If necessary, delete the existing profile:
     • Open Control Panel.
     • Navigate to Mail and select Show Profiles.
     • Remove the problematic profile.
4. Create a New Outlook Profile:
   • In Control Panel, go to Mail and select Show Profiles.
   • Click Add and enter a name for the new profile.
   • Set up the email account and click Finish.

We believe that following these steps will help resolve the issue. However, if you continue to experience difficulties, please provide additional details: 

• The screenshot of the error message
• Are you using New Outlook for Windows or Classic Outlook for Windows?
• Share your Outlook version and product details: 
  • For New Outlook: Go to Settings > General > About Outlook.
  • For Classic Outlook: Navigate to File > Office Account.
  • Take a screenshot of the entire page (excluding personal information) and share it with us.

Reference: What version of Outlook do I have?This information will assist me in understanding the issue better and help me find a solution.Thank you in advance for your understanding. Your patience and cooperation will be greatly appreciated. Wishing you all the best!

Sincerely Feroz Mahmud | Microsoft Community Moderator

Answer 2

Hello Feroz,

Thank you for your message. I tried your steps to the extent that were possible for me. I could not carry out step 1, as I do not have "Microsoft Office" among my installed apps - I had Outlook installed through the Office 365 app. But I did uninstall and install again Outlook. I could not do step 2 either, as my work account is managed by my company. I did steps 3 and 4.

After trying the "Try the new Outlook" toggle again I did see some new screens I did not see before. However, just as I was attempting to configure my work email account again I received a new similar error (which thankfully I can post as a screenshot here today):

The program seemed to hang when showing the error too, and I had to forcefully close it through the task manager.

If I try to start the program again I get a similar though not exactly identical error (the URL of the JavaScript file is different, although I assume the problem is in the data received from the server and not in the client scripts):

For more details:

* I am trying to transition from Classic Outlook to New Outlook.

* My Classic Outlook version is "Microsoft® Outlook® for Microsoft 365 MSO (Version 2402 Build 16.0.17328.20282) 64-bit"

Thanks,

Javier

Answer 3

Since it disappears on restart, I suggest that the CDN is bobbling it. (Berlin, CT) -ex SQE tech

Answer 4

Hello,

I have the same problem. I've tried all the mentioned steps but didn't work out. I was using the new outlook. Now it switched back to the classic outlook. Version 2406 (Build 17726.20160 click-to-run)