A family of Microsoft word processing software products for creating web, email, and print documents.
Dear Tiago Santos,
Good day!!
Apologies for the inconvenience caused and please don’t worry, let’s work together on your concern and move towards a resolution path.
I understand your concern and would like to confirm whether the same problem happens when you access the Microsoft Teams in the browser.
If there is no problem in accessing the Microsoft Teams in the browser, I would like to confirm whether the proxy, firewall, VPN, or antivirus is enabled on your device. If yes, please turn off them temporarily and check whether the same issue happens.
If none of them are enabled but the same issue happens, please clear the Teams application cache and restart your device to see whether we can sign-in without any issue: Clear the Teams cache - Microsoft Support
If nothing works, I would like to request you download and install the Microsoft SARA tool to troubleshoot the Teams log in issue (Unable to sign-in to Teams applications):About the Microsoft Support and Recovery Assistant - Microsoft Support
If still the same problem happens, If the same problem persists, we apologize and I believe the problem should be further investigated by related development team via collecting Fiddler logs because there is no any related service incident reported at the Microsoft Service Health dashboard.
I do feel regret for not resolving the problem and redirecting you to the related development team but the fix to your concern can be find out through the Fiddler logs and suggest you raise a support ticket from the Office 365 admin center, where the related team will investigate the problem further by collecting the Fiddler logs.
Reference: Get support - Microsoft 365 admin | Microsoft Learn
Note: To create a support ticket, you need to have admin privileges and if you aren’t admin of your Office 365 organization, please contact the admin of creating a new ticket.
Appreciate your patience and understanding. Have a great day!!
Best Regards,
Sophia