Hello, thank you for reaching out to Microsoft Q&A.
Do you get any error code or message when accessing your Outlook emails, or has it been deleted?
Open an incognito tab and sign in with your Microsoft account here-
If you receive any error, please share the complete error message.
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In addition, it is recommended to protect your account with a strong password and enable two-factor authentication for added security.
1. Reset your Microsoft account password.
Open an InPrivate/Incognito browser window and use the following link to reset your password: https://account.live.com/ResetPassword.aspx
2. Sign out of your account from all sessions.
Once the password reset is successful, sign in with your account here: https://account.live.com/proofs/Manage
Scroll down until you find Sign out everywhere. Select Sign out everywhere.
3. Enable two-step verification.
On the Security settings page, under Additional security, turn on Two-step verification. Make sure you have at least three security verification methods active.
After you have enabled these security protections, sign out of your account in the Outlook app and sign back in with your new password.