Error code CAA90049 - Any M365 App

Anonymous
2024-04-08T18:25:48+00:00

Hello, I have a remote end user that is receiving this error code when trying to sign into any M365 app. Once we close the error message the apps work perfectly fine but this happens daily when signing on and I would like to find a permanent fix. I would attach a screenshot but that doesn't seem to be working right now.

  • User enters login credentials and Microsoft authenticator code then this error pops up for any m365 app / teams / OneDrive.
  • User is in another state so can't come into office.

Something went wrong

We couldn't sign you in. If this error persists, contact your system administrators and provide the error code CAA90049.

Error code: CAA90049

Correlation ID: 9a55***1d07

Server message: Session key is empty

Any help is appreciated.

Thank you

[PII is removed by moderator]

Microsoft 365 and Office | Subscription, account, billing | For business | Other

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  1. Anonymous
    2025-01-24T18:09:08+00:00

    Hi,

    In my case, it would only be enough for the user in the A365 administrator to delete the Microsoft 365 activations and close all active Microsoft 365 connections.

    Thanks,

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  2. Anonymous
    2024-12-17T21:46:51+00:00

    Thanks for this, after running this command it fixed the issue.

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  3. Anonymous
    2024-10-16T09:49:28+00:00

    I just had this same problem with a customer.

    Fixed it by removing the computer from Entra and running dsregcmd /forcerecovery on the computer.

    I also emptied the following folders but I'm not sure thats required with the above steps.

    %localappdata%/Microsoft/OneAuth

    %localappdata%/Microsoft/IdentityCache

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  4. Anonymous
    2024-09-22T23:56:17+00:00

    Guys!

    Please remove your work account from settings, disconnect the device from the organization, and then re-add it and sign in again. That fixed my issue.

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  5. Anonymous
    2024-09-18T19:09:58+00:00

    UPDATE:

    The registry key:

    HKLM\SOFTWARE\Policies\Microsoft\Windows\WorkplaceJoin
    "BlockAADWorkplaceJoin"=dword:00000001

    Does seem to be working. I had to reboot the servers a couple of times before I actually saw a change.

    I will keep monitoring and report back with issue.

    Thank you cf34!

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