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Anon4343's avatar
Anon4343
Brass Contributor
Apr 07, 2021

Unable to Log Into Teams on iPhone. Error: Sign-in Error

Hello,

 

Has anyone been able to resolve the Sign-In Error issue? It appears to be an issue between the Microsoft Authenticator app and Teams. Our organization is using Conditional Access policies to require MFA via the Microsoft Authenticator App. After MFA completes and the phone returns to Teams, the error message is displayed. Azure AD Sign-In log displays MFA success.

 

Steps to produce:

 

1. Open Teams
2. add account tscbank.com
3. select work account
4. Flips to Microsoft Authenticator
5. Enter Password
6. Flips to Teams
7. Displays error: Sign-In Error

 

Here is what I've tried:

 

- deleted the account from Teams
- restarted the phone
- reinstalled teams
-  tried to delete cache from Teams settings in iOS General (never seems to clear)
- removed email address from personal Microsoft account

  • It looks like the issue was caused by Teams not applying an InTune policy. We're using InTune to manage Teams. For some reason, teams wasn't applying the organization's data management policy and was getting blocked. Teams wasn't showing the user that this app will be managed and needs to be restarted.

     

    The resolution was to receive a message in Teams and not view it. Eventually, the user will receive an email stating that a teammate is trying to reach you in Microsoft Teams. Within that email, there is a link to 'Reply in Teams'. If the user opens that link on their mobile device, it correctly initiates data management policy and manages Teams. The user was able to successfully log into Teams.

  • Anon4343's avatar
    Anon4343
    Brass Contributor

    It looks like the issue was caused by Teams not applying an InTune policy. We're using InTune to manage Teams. For some reason, teams wasn't applying the organization's data management policy and was getting blocked. Teams wasn't showing the user that this app will be managed and needs to be restarted.

     

    The resolution was to receive a message in Teams and not view it. Eventually, the user will receive an email stating that a teammate is trying to reach you in Microsoft Teams. Within that email, there is a link to 'Reply in Teams'. If the user opens that link on their mobile device, it correctly initiates data management policy and manages Teams. The user was able to successfully log into Teams.

      • Anon4343's avatar
        Anon4343
        Brass Contributor

        VAM_21 

         

        Sometimes closing authenticator, teams, and outlook. Then, open Outlook and sign in again resolves the issue.

    • Anon4343's avatar
      Anon4343
      Brass Contributor
      It did not. I'll post there as well. Thank you.
  • User1001's avatar
    User1001
    Copper Contributor

    Anon4343 I had the exact same issue. The following solution worked for me:


    1) Open Microsoft Authenticator app.

    2) Delete all accounts.

    3) Open the navigation bar/hamburger menu (upper left) > Settings > Device Registration.

    4) Log-in to your account.

     

    Source

  • brightwolf's avatar
    brightwolf
    Copper Contributor

    Anon4343 

    I had a similar problem, suddenly could not join Teams meetings on my iPhone anymore because I had no internet, according to the app. But my iPhone was connected to the internet, other apps were connecting fine.

    My solution was, go to Settings > Find the settings for Teams in the list of apps > Tick "Mobile data". Somehow this was switched off.... 

    Hope this helps someone.

  • Willjoe2442's avatar
    Willjoe2442
    Brass Contributor
    It appears to be an issue between the Microsoft Authenticator app and Teams. Our organization is using Conditional Access policies to require MFA via the Microsoft Authenticator App. After MFA completes and the phone returns to Teams, the error message is displayed. Azure AD Sign-In log displays MFA success.

    Regards
    Will
  • julianhead's avatar
    julianhead
    Copper Contributor

    Anon4343 have had similar issue for months. microsoft useless im afraid (4 months of support with them refusing any face to face support in person).

     

    i solved it myself

     

    i could access my work microsoft account for teams and office on all devices (iPad, pc, mac) except my iPhone, my personal microsoft account was unaffected - despite me seeing in the authentication app both work and personal accounts.

     

    I went into the portal (https://myaccount.microsoft.com), selected security info, and added another sign in method for my work microsoft account (selected authenticator app from the drop down), clicked next and scanned the QR code using the iPhone. This miraculously wrote over the top of the existing work account authentication and hey presto - full access on my iPhone.

     

    Hope that helps

    • Anon4343's avatar
      Anon4343
      Brass Contributor

      julianhead It sounds like you re-added the authenticator app registration to your phone despite it working most of the time. Interesting. We haven't seen this issue in quite some time. For me personally, I switched to Android and haven't had this issue.

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