Hi @Aananoyms ,
A quick search on the error message led me to the similar thread below. From the discussion over there, the error was finally resolved by removing unnecessary admin roles assigned to the user account:
500 error on login to outlook.office365.com X-Redir-Error
If this applies to your situation as well, please login to the Microsoft 365 admin center using another admin account (Per my test, you cannot edit the role settings of your own account. You can create a new admin account or reach out to another administrator to complete the task.). In the left navigation pane, select Users > Active users, select the account you are having the issue with, click "Manage roles" under "Roles", remove all other unnecessary roles.
If the above doesn't work, could you clarify the things below for further discussion?
- Are you able to use the email account in Outlook desktop client smoothly?
- Is this a suddenly occurred issue?
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