Cannot connect to MTeams on Mozilla Firefox Ubuntu 24.04 LTS

Laborie, Alexandre 0 Reputation points
2026-04-30T14:34:12.6233333+00:00

Hi,

I guess everything in the title. My Teams account is an institutional one. The connect button is numb. It works with other web browser though. Anyone having the same issue?

Microsoft Teams | Microsoft Teams for education | Sign up and Sign in | Sign in
0 comments

2 answers

Sort by: Most helpful
Most helpful Newest Oldest
  1. Jay Tr 13,455 Reputation points Microsoft External Staff Moderator
    2026-04-30T17:57:30.48+00:00

    Hi @Laborie, Alexandre, 

    I hope you are doing well. 

    Thank you for sharing those details. Since Microsoft Teams works in other browsers, the issue appears more likely to be related to Firefox settings rather than the institutional account itself. Teams on the web is supported in Firefox, and browser permissions and cookie settings can affect whether Teams loads and signs in correctly.  

    Step 1: Allow camera and microphone permissions for Teams 

    1. Open Firefox and go to Settings > Privacy & Security. Under Permissions, find Camera and select Settings. 

    User's image 

    1. Make sure the Teams site is allowed. Then do the same for Microphone and save the changes. After that, refresh the Teams page and test again. 

    Step 2: Allow Teams cookies in Firefox    

    1. In Settings > Privacy & Security, go to Cookies and Site Data and select Manage Exceptions.   

    User's image

    1. Add the following sites one by one and set each to Allow: 
    1. Then select Save Changes. These trusted cookie exceptions can help Teams complete the web sign in flow correctly. 

    Step 3: Check Firefox tracking protection 

    Still under Privacy & Security, check whether Enhanced Tracking Protection is set to Strict or Custom.  

    User's image

     

    If it is, try temporarily switching it to Standard, then reload Teams and test again, since stricter tracking protection can interfere with some site functionality.  

    Step 4: Refresh Teams and test sign in again 

    Once the permissions and cookie settings have been updated, close the Teams tab, open it again, and try signing in once more.

     

    I hope this information is helpful. Please follow the steps above and let me know if it works for you. If not, we can continue working together to resolve the issue.  

    Thank you for your patience and understanding. If you have any questions or need additional assistance, please don’t hesitate to reach out so I can continue to support you. If you found the response useful, please consider marking it as accepted, as this may help other community members who are looking for similar guidance.  

    I look forward to continuing the conversation.  

    If you have extra questions about this answer, please click "Comment". 

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.     

    Was this answer helpful?

  2. AI answer

    2026-04-30T14:34:26.57+00:00

    In Firefox on Ubuntu, Teams sign-in and buttons can fail if the site or its cookies/permissions are blocked.

    Try these steps in Mozilla Firefox:

    1. Allow camera/microphone for Teams (also confirms site permissions are working):
      1. Open Firefox Settings.
      2. Select Privacy & Security.
      3. Under Permissions, find Camera and Microphone, then select Settings.
      4. Make sure access is allowed for the Teams site.
      5. Close Settings, then refresh the Teams app in your browser.
    2. Check that Teams is not restricted by Trusted Sites / cookie settings:
      • If using any “Trusted Sites” or strict tracking/cookie settings, ensure the Microsoft Teams URLs are allowed so the client can load properly. When Teams URLs are not trusted, the app may stay on the loading screen or buttons may not respond.
    3. If Teams still does not load or respond in Firefox:
      • Try opening Teams in a private/incognito window with default settings and sign in again.
      • If an ad blocker or privacy extension is enabled, temporarily disable it for the Teams site and reload.

    If the account is an education/institutional account and the issue persists only in Firefox, contact the institution’s IT admin to confirm there are no browser-specific policies blocking Teams sign-in.

    References:

    AI-generated content may be incorrect. Read our transparency notes for more information.

    Was this answer helpful?

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.