Hi, I'm John! I will help you with this.
There was actually a recent known issue with Outlook/Hotmail, especially affecting iOS/iPad devices. Microsoft has already fixed the service issue, but some users still need to re-enter their password to get emails syncing again. Source: https://portal.office.com/servicestatus
Right now, most cases like yours are fixed by re-adding or updating the account.
If you’re using Apple Mail (default app):
- Go to Settings > Mail > Accounts
- Tap your email account
- Tap Account Settings / Password
- Re-enter your password
- Save, then open Mail again
If that doesn’t work, remove and add the account again.
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