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]

Once they applied that in our Citrix environment it stopped wanting to register the device and the error went away for us.

This did not work. In fact, now users cannot sign in at all.

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!

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.

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

Error code CAA90049 - Any M365 App

Anonymous

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]

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

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67 answers

Anonymous

2024-09-17T21:09:31+00:00

Once they applied that in our Citrix environment it stopped wanting to register the device and the error went away for us.
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Anonymous

2024-09-17T21:47:17+00:00

This did not work. In fact, now users cannot sign in at all.
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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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1 person found this answer helpful.

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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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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
Was this answer helpful?

4 people found this answer helpful.

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