Can't sign in to the Outlook mobile app

Hello, are you signed in with any account already in iPhone Settings under Mail or Accounts?

On iPhone, go to Settings, tap Mail, then Accounts, remove the email account from there if it exists, then go to Settings, General, Transfer or Reset iPhone, tap Reset, then choose Reset Network Settings, after the phone restarts open Outlook and sign in again, this refreshes account credentials and network configuration which can fix the sign in error.

Try these steps in order to troubleshoot sign-in issues with the Outlook mobile app:

1. Confirm the type of account being used
   • If it is a Microsoft personal account (Outlook.com, Hotmail, Live, MSN), run the sign-in helper tool, which checks the account and guides through fixes: Start.
   • If it is a work or school account (Microsoft 365), use the self-service password reset page if enabled by the admin: Reset password. Otherwise, contact the organization’s IT admin.
   • If it is a non-Microsoft account (Gmail, Yahoo, iCloud, etc.), contact that email provider for sign-in issues.
2. Make sure the Outlook app is up to date
   • Recurring or unexpected sign-in errors can occur if the app does not meet current security standards. Install or update to the latest Outlook for iOS from the Apple App Store: download the latest version.
3. Verify username and password outside the app
   • Open a browser on the device and sign in to the same account (for Microsoft 365 or Outlook.com) to confirm the username and password work correctly.
   • If sign-in fails in the browser as well, resolve that issue first using the sign-in helper or password reset links above.
4. Check for account blocks or access restrictions
   • If the account is a work or school account and access to Outlook mobile has been blocked by policy, the sign-in will fail. In that case, only the IT administrator can unblock or allow the account to use Outlook for iOS.
5. If still unable to sign in
   • For Microsoft personal accounts, use the sign-in helper again and follow any remediation steps it provides.
   • For work or school accounts, contact the IT administrator and provide the error details from the app so they can check account status and policies.

References:

• Can't sign in to the Outlook mobile app
• What you can do in the Microsoft 365 apps on mobile devices with a Microsoft 365 subscription
• Access Denied: Login Error
• Get help with Outlook Lite for Android