Hi Daniela,
May I confirm which type of Office 365 are you using, for example, Enterprise plan?
If you obtained your Office 365 account via an organization, it’s recommended you contact the administrator of your organization to get your account information.
If you are a Small Business Office 365 user and don’t have an administrator, I suggest you try to find your account information via any email history. Alternatively, you can search for the confirmation email when setting up Office 365 with the subject “Get Started with Microsoft Office 365” from your alternative email address.
For more information: We don't recognize this user ID or password" error when a user tries to sign in to the Office 365 portal
Please feel free to post back if you have any further questions.
Thanks,
Evan Zhang
