Why can’t I sign into my Gmail or Outlook.com email on a new device?
There could be many reasons, but the underlying cause I’ve been encountering lately is App specific passwords. A lesser-known security feature associated with two-step authentication, these unique passwords are device and app specific. Therefore, if a specific device is compromised, lost, or stolen – then access to that device is revocable. The password on your phone is different from the one on your desktop email client which also differs from the account’s main password. These unique passwords can be generated from the account’s security dashboard (links below). Access to any device set up using this method may also be withdrawn through the account security dashboard.
You could be having trouble configuring your account on a new device, or your desktop email client simply won’t accept your correct account settings. Before pulling out your hair in angst, remember that you might simply need to generate an app specific password.