Account doesn't exist with my MS Online account - false response

Question

Account doesn't exist with my MS Online account - false response

Lynne Greco 0

I am trying to log in with a KNOWN GOOD account. Everytime we login into our MS business account it says we dont have an account with this error...Example: [Moderator note: Personally Identifiable Information removed] @contoso.onmicrosoft.com or [Moderator note: Personally Identifiable Information removed] @contoso.com The email or username you entered does not exist. Please check that you have typed your email or username correctly.

However, we go through the password reset and it works just fine FOR THAT LOGIN, but reverts back to the NEXT attempt with account doesn't exist...we do the password reset and it works again.

This is a small account with 4 users and we are not running Entra that I am aware of.

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Answer 1

Dora-T 1,130 Independent Advisor

Hi @Lynne Greco

To better understand your issue, could you please provide the following information?

-Where does the error occur when you try to sign in? For example, does it happen in a web browser, Outlook, a mobile app, or another Microsoft 365 application?

-Are you able to sign in successfully to the Microsoft 365 portal at https://portal.office.com?

-Does the issue affect only this account, or are all four user accounts experiencing the same issue?

-Were you able to sign in successfully with this account previously, or has the account never been able to sign in successfully?

In the meantime, you can also try the following basic troubleshooting steps:

-Open an InPrivate or Incognito browser window and try signing in again.

-Clear the browser cookies and cached credentials related to Microsoft 365.

-Try signing in from a different browser or device.

Please let me know how it goes and share the results of the above checks.

Lynne Greco 0 Reputation points

2026-09-17T00:58:15.3066667+00:00

It is not working on the MS 365 portal or other MS online accounts. We have to "reset" the password whenever I try to log in

I thought it could be an Entra ID issue, but Entra is saying I am a user and throwing several errors there. How do I find out who the admin is on the account? It should be me since I set up our MS365 account using this same email and no one changed anything that I recall.

I also tried logging into amin.microsoft.com and getting the same error about not recognizing the account.
Lynne Greco 0 Reputation points

2026-09-17T01:03:31.5166667+00:00

here is the error I am getting in Entra:
Lynne Greco 0 Reputation points

2026-09-17T01:06:51.8833333+00:00

Here is another log in example
Dora-T 1,130 Reputation points Independent Advisor

2026-09-17T07:00:24.0733333+00:00

Hi @Lynne Greco

Based on my research, the AADSTS16000 error indicates that the sign in is being handled through the live.com identity provider and is being directed to the Microsoft Services tenant. Similar cases can occur when the sign in process is using a personal Microsoft account instead of the work or school account associated with the Microsoft 365 tenant.

To help narrow this down, could you please confirm:

-Do you still have access to the original onmicrosoft.com account that was created when the Microsoft 365 subscription was set up? If so, could you try signing in from an InPrivate or Incognito browser window and check whether you can access the Microsoft 365 admin center?

-When you reset the password, are you resetting it for the custom domain account or the original onmicrosoft.com account?

-Were you previously able to sign in to the Microsoft 365 admin center with the account you are currently using?

Please let me know how it goes.
Dora-T 1,130 Reputation points Independent Advisor

2026-09-18T00:28:12.3433333+00:00

Hi @Lynne Greco

Is there any update from you?

If yes, please feel free to let me know.
Lynne Greco 0 Reputation points

2026-09-19T15:54:00.8233333+00:00

@Dora-T sorry for the delay, the IT support guy is only available on a part time basis evenings and weekends.

He was able to log in via a Google In-cognito browser using the [Moderator note: Personally Identifiable Information removed]@smvparish.org login with our current password. and able to open our account as well.

We have a MS 365 Family account, not a business account. I think that might explain the issues with the admin.microsoft (I think that is for business accounts only).

But that still doesn't explain the issue with failed log in attempts on the Windows Microsoft Edge browser.
Lynne Greco 0 Reputation points

2026-09-19T15:57:34.46+00:00

@Dora-T

I tried to log in again on the MS Edge browser with the [Moderator note: Personally Identifiable Information removed]@smvparish.org and got the same response that @smvparish.org does not exist in the system. Just wanted to confirm that is still the issue.
Dora-T 1,130 Reputation points Independent Advisor

2026-09-21T01:03:23.7133333+00:00

Hi @Lynne Greco

Since the same account was able to sign in successfully using Chrome Incognito, could you please try the following in Microsoft Edge? This will help determine whether the issue is related to Edge's cached sign in data, extensions, or the current Edge profile.

-Open an InPrivate window in Edge and try signing in again.

-If the issue still occurs, sign out of all Microsoft accounts currently signed in to Edge.

-Clear the cookies and cached site data for Microsoft websites.

-Temporarily disable any browser extensions that may affect the sign in.

-If possible, create a new Edge profile and test the sign in there.

Please feel free to share the results once you have a chance to try these steps.
Dora-T 1,130 Reputation points Independent Advisor

2026-09-22T01:32:43.21+00:00

Hi @Lynne Greco

Just checking in to see if you've had a chance to check my previous response.

Please let me know if there are any updates on your end.