Microsoft 365 login problem on latest Canary 27842

Does anyone else with this issue also have problems connecting to a machine with the Windows app (fails with authentication errors)? That started at the same time as this for me and has also stayed consistent over the last 3 flights.

For now, I have withdrawn all units I have from the Insider program. I wonder how such significant errors can be allowed, with the next Canary builds being published so rarely (which is now every 2-3 weeks). There is definitely a lack of effective supervision over what is released to testers, as well as efficient implementation of fixes to identified, after all significant errors.

In particular - with all due respect to the work of the MS Team - I do not understand how it is possible to publish builds that do not work correctly with Microsoft paid services. Such builds should go to the trash and not to the insider channel.

I will add that the error does not occur in the current release version of Windows 11 (after exiting the Insider program and installing the release version on all computers where I had the described problem).

microsoft how long it will take to resolve this issue . i am also facing the same issue. Either need to do the clean format or wait for the solution

The epic continues and the situation changes like in a kaleidoscope. Being logged into a working Outlook 365 Copilot where I see an active Microsoft 365 Family subscription, I start the Outlook classic version and receive information about the lack of an active subscription, a login error and a message about the inability to open the program, set of folders and log in to the Exchange service.

And in the morning Outlook Classic was fully working for me.

Correlation Id: f48749f0-b79a-4e3f-b1b0-fcb67bb02294

Timestamp: 2025-05-15T16:26:33.000Z

DPTI: 75cda5c094521eaa31eaf7ae043d961503a2255fcd326a1bd832108f0fc611a2 

Message: An unexpected error occurred.

Tag: 9bxf9

Code: 1813

Unfortunately, today another, second long-term attempt by Microsoft support to repair the problem I described (using the quick help module) also ended in failure. Finally, in order to receive help, I was sent to the link Home | Microsoft Community Hub

I kindly ask the developers to urgently verify the causes of the problem, because I have lost the ability to use the resources of the Microsoft package. I keep my fingers crossed that the next Canary build will not contain this error

Unfortunately, today the problem has also moved to Outlook classic I receive a server connection error (services connected in the account tab) and when I try to bypass the error by logging in again, I get the following message

Correlation Id: 63628c8a-801a-4c7a-9731-3efff75f1646
Timestamp: 2025-05-14T04:35:41.000Z
DPTI: 75cda5c094521eaa31eaf7ae043d961503a2255fcd326a1bd832108f0fc611a2
Message: An unexpected error occurred.
Tag: 9bxf9
Code: 1813

Two more additional comments:

1. I can use Outlook normally lol (I am also logged in on the desktop version) 
2. Trying to enter Access ends with the following message:
   
   

    

Continuing with the problem described.

First of all, I would like to point out that the current status applies to both the Microsoft 365 version - i.e. 16.0.18730.20142 (which I have on my desktop computer) and version 16.0.18829.20000 (which I have on my laptop), although in the online (browser) and Copilot versions I remain logged in normally (the error does not pop up here). The problem therefore concerns only the so-called Microsoft 365 desktop application, both in the insider beta version and the base version, downloaded from the Microsoft 365 website.

Yesterday, on my laptop, the reported error of the Microsoft 365 desktop version has changed slightly, although I still get the login error 2604. However, as you can see in the screenshot of the Microsoft 365 account tab, I am indicated as logged in ("product subscribed to by ..........") and at the same time on the left side I get a message about the need to log in again (however, such an attempt ends with error 2604) and another error displayed after trying to re-enter the login email (error 9bxf9).
In turn, at the bottom of the Microsoft 365 account tab I constantly have a message about the inability to display online services and pressing the "try again" button ends without effect and without changing the message.
Unfortunately, on my desktop computer - in the desktop version of Microsoft 365, I remain - as I wrote earlier - logged out without the option to log in (it gives me errors 2604 and 9bxf9), which prevents me from working in the Microsoft 365 package and probably even from downloading the latest insider version.

I will also add that attempting to use the license verification option in the account tab of the Microsoft 365 desktop application on my laptop also ends with error 2604 and a suggestion to contact support if the error persists.

In turn, using the Manage Account option in the same Microsoft 365 tab correctly takes me to the Microsoft account page where the active subscription is displayed :)
Black magic. I'm counting on the help of the Esteemed Microsoft developers because things are happening that I don't understand :(

Another new - interesting observation.

If I create a Word file in Microsoft 365 Copilot, I can work in it and have access to it as long as I do it from "My OneDrive" on the network. However, if I try to save the file to the desktop or even to the Onedrive folder on my PC and then open the file from Microsoft 365, I get a connection error message 2604 and a login requirement that cannot be performed.

The problem with the pop-up message "This content is a potential security issue. Do you trust this content?" concerns files that I try to open through Microsoft 365 Copilot, and which I do not have in "My Onedrive" on the network, but are on the desktop (or in the Onedrive folder on my computer). Files outside of "My Onedrive" on the network are not classified as those that I own, which generates an access problem.

In my opinion, the problem lies with the Microsoft 365 application itself, as the same situation repeats itself on several computers that I have access to and from different users within Microsoft Family, regardless of the type of internet connection (and different network providers) or profiles.

I will add one more note:

When I create a new file, e.g. Word on the desktop, I cannot open it from either Microsoft 365 or Microsoft 365 Copilot. The first program asks for a login, the second displays the prompt I wrote about ("This content is a potential security problem. Do you trust this content?" - the file does not have my ownership) although in the second I have the status of a logged-in person.

On the other hand, if I create a Word file in Microsoft 365 Copilot and save it to the desktop, then - as I wrote - I can work on it and open it from Copilot (where I have no problem with logging in/licensing), but from the regular Microsoft 365 level I get a login request, error 2604 or 2603 and activation block despite an active license on the Microsoft account.

I put also my service request topic on Microsoft 365 Insider forum here:

https://answers.microsoft.com/en-us/officeinsider/forum/offinsd_access-offinsdsub_win/microsoft-365-login-problem-on-latest-canary-27842/6d832ef4-9913-4b59-82d9-7619ec82ec69