Error code CAA90049 - Any M365 App

Question

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]

Answer 1

Hello to further explain the Issue,
every time i open any Office 365 App i have to login again. and either it just takes the login , but only untill i close the app and open it again then like i said i have to sign in again.
Or this error Windows Accurs with Error Code CAA90049 after the microsoft Windows Asks me to remember the Login for other Apps.
then im signed in but after i close the app and reopen i have to sign in again.
ive got the 365 Business Premium Licence.
It looks like its a kinda new error and maybe caused by latest Windows Update ?

Answer 2

Did anyone find a solution to this issue?

Answer 3

Do u have any update, I'm facing the same issue

Answer 4

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

Answer 5

Same here!!