I keep getting error code 9n155 while sign in for MS365.

Question

I keep getting error code 9n155 while sign in for MS365.

NKO 0

Hi,

I am facing this issue for few weeks and unable to sign in MS365. I am using Mac 2024 with update software.

I get this message while sign in MS 365:

Correlation Id: 60442844-a2a7-4143-b80a-5e3001c84f34

Timestamp: 2025-01-22T15:51:52.000Z

DPTI: a90198b6dc681ca44aae0d8367a4ba5265f6f28fe816a295c28c106f9562842f

Error Tag: 9n155

Error Code: 0

I have tried all options mentioned in other thread including start in safe mode, re installl software etc.

Still cannot get rid of this issue.

I have not created another account as I will not be able to use my privilege with new account to sign in.

Thanks in anticipation

2 answers

Your answer

Answer 1

Jiajing Hua 18,060 Moderator

Hi @NKO

Welcome to the Q&A forum.

It seems that you cannot sign into Office apps successfully, could you please log in to office.com for a check?

Which type of account you are using, personally account or organizational account?

If there is no problem logging in to the link above, I suggest you can delete Office related cache files:

Open Finder.

Press Command + Shift + G, then type ~/Library/Containers/com.microsoft.office, and then press Enter.
Delete the contents of the folders related to Microsoft 365 (be careful not to delete other important files).

Besides, clear your credentials:

Open Keychain Access.
Search for any entries related to Microsoft Office and delete them.
Restart your computer and try to sign in again.

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NKO 0 Reputation points

2025-01-23T13:27:34.2966667+00:00

Thanks for support,

I am using organizational account. I have deleted all cache related to Microsoft but still same error code 9n155.
Jiajing Hua 18,060 Reputation points Moderator

2025-01-24T09:27:25.8733333+00:00

Hi @NKO
Thanks for your back.

Could you please share us with an error screenshot?

As I mentioned above, please check whether you can sign into https://portal.office.com/account properly.

Besides, if possible, can you sign in this business account in Office apps on other Mac devices?

Currently, please try the tool in "How to remove Office license files on a Mac", then re-start your machine, sign in your account for a check.
NKO 0 Reputation points

2025-01-24T12:35:48.9+00:00

Thanks for your support, I can log in on portal.office.com link you provided.

I also cannot sign in the other Mac devices, similar code appearing.

I have use " office license removal tool", and reinstall office and still getting same error.

I have unique identifier number for my ID, any use??

Thanks for your support
NKO 0 Reputation points

2025-01-27T13:51:33.8133333+00:00

Hi, can you please help with this error?
Jiajing Hua 18,060 Reputation points Moderator

2025-01-28T06:18:21.01+00:00

Hi @NKO

Thanks for your response and sorry for the late.

I also cannot sign in the other Mac devices, similar code appearing.

According to this, I think this issue is related to your account and account-related settings. Please contact the IT in your organization for assistance.

It's best check whether there is any condition access policy on your account, that block you signing on apps for Mac.

Besides, reset the MFA if your account has this verification.

Thanks for your understanding.
NKO 0 Reputation points

2025-01-28T09:26:32.1866667+00:00

Thanks for support.

I have old sign in iphone and another mac and it is till working, but unable to sign in new mac I bought last week.

I spoke to IT several times, but they are unable to sort it out and according to them no issue with account setting from organization.

How to reset MFA as You mentioned earlier?

Thanks
Jiajing Hua 18,060 Reputation points Moderator

2025-01-29T06:31:25.2133333+00:00
Hi @NKO

To reset MFA, it need IT's help. The reference: Manage user authentication options.

I have old sign in iphone and another mac and it is till working, but unable to sign in new mac I bought last week.

It means that now, you can sign into your business account on old Mac, but fail on the new one, am I right?

Have you updated the MacOS and Office apps to the latest?

You may also try to create a new user on Mac, and test this issue in new Mac user account.

If nothing helps, I still suggest you contact IT for troubleshooting, IT can also check the Microsoft Entra sign-in logs to narrow down.

Answer 2

Anton 1

Posting this for whoever finds this thread while googling for a solution to this rare issue.

In my case the problem was solved by searching for my User ID (in GUID format) in macOS Keychain Access and deleting all matching entries in the "login" keychain.

Prior to that I have tried searching and deleting all entries matching the username (in email format) but that was not sufficient.

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I keep getting error code 9n155 while sign in for MS365.

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