Multifactor authentication not working as it should

[Noffe69]

We're using Office 365 as our work emails and I've activated Multifactor authentication on my account.

It's allowed to install the programs on up to 5 different computers and I've only need for 2,

So I let my sister use one of those licenses so she can use it when she applies to jobs and such.

The problems comes when she gets links to meetings in Teams, despite the fact the only her is logged in in Teams it open MY account without asking for my multifactor authentication.

We haven't found a way to open the links in the app using her account so the workaround for now is to use the webbrowser 

I posted an image that show how we are logged in on the Office apps on her computer

[#2]

Hello, once MFA has been satisfied you will not get another prompt until your 'session lifetime' expires and easily explained the default is a rolling window of 90 days.

It sounds to me as if your account is added under the W10 account settings on her computer making it the primary account as Teams defaults to domain-joined accounts.

[#3]

@ChristianJBergstrom 

Which mean despite she's logged in as herself on the computer and using her account already in Teams when she's using a Teams meeting link it say "I don't give sh... about what she want", she's using a personal account and since I have here an account that's a work account I'll use that despite the fact it isn't used to anything else than activating Office.

I'll say that an BIG bug in Teams handling of accounts.

Despite if I remove my account from W10 account settings then the Office activation also stops working.

[#4]

It's because you're not using the correct licensing. You cannot share a Business subscription this way, you'll need "Family" for up to six people (I think it is). As for the above, when your account is being added there the laptop is added as 'Azure AD registered' and part of your business org. Hence, using the Azure AD WAM plugin to get a Primary Refresh Token (PRT). The PRT uses refresh tokens and access tokens for enabling SSO (single sign-on) so perhaps you now understand that the scenario isn't optimal and Teams literally trying to do whatever it can to use your account (as well as other apps).