How to fix this error? / Mobile phone Outlook log-in error

Question

How to fix this error? / Mobile phone Outlook log-in error

[Moderator's note: PII removed]

Message: The credential is invalid.

Tag: 48bhe

Code: 0

Answer 1

Dear @(학부생) 주현진 (생명과학과),

I apologize for any inconvenience you may encounter when using our services/ products. To help you with the issue, we need more specific information from you:

• Could you please confirm if the account having this issue is a business/ school account or a personal account?
• Please help me to provide a screenshot of the issue?

In the meantime, kindly try these following steps:

• Go to Outlook > log in to reconfirm your password.
• Uninstall and reinstall Outlook app on your mobile devices.

Please refer to this article Can't sign in to the Outlook mobile app - Microsoft Support.

Providing these details will allow me to support you in a timely and efficient manner. I am looking forward to hearing from you.

Answer 2

Based on the error message “The credential is invalid” when signing in to Outlook for iOS, the issue is typically with the username, password, or how the account is being entered.

Try the following steps in order:

1. Verify username and password
   • Carefully re‑enter the password, ensuring correct capitalization and no extra spaces.
   • If this is a work or school Microsoft 365 account and the password might be wrong or expired, reset it using the self‑service portal if allowed: https://passwordreset.microsoftonline.com/
   • If self‑service reset is not allowed, contact the organization’s IT administrator to confirm or reset the password.
2. Use the correct sign‑in name (UPN vs email alias)
   • For work or school accounts, the sign‑in name may be the domain UPN, which can differ from the visible email address.
   • Example: sign‑in UPN ******@constso.com vs email address ******@contso.com.
   • If unsure, ask the IT administrator for the correct UPN to use in Outlook for iOS.
3. Confirm the account works in a browser (OWA/Webmail)
   • Open a browser on the mobile device or a computer and sign in to the organization’s Outlook on the web/OWA portal using the same username and password.
   • If sign‑in fails there as well, the account itself needs to be fixed by the IT administrator (password, lockout, or other account issue).
4. If the account is blocked from Outlook mobile
   • If the organization has blocked Outlook mobile access, the sign‑in can fail regardless of correct credentials.
   • Only the IT administrator can change this; contact the admin to confirm whether Outlook for iOS is allowed for the mailbox.
5. If nothing else works
   • Remove the Outlook app from the phone and reinstall it from the app store to ensure the latest version and a clean sign‑in flow.
   • Then try signing in again using the confirmed correct UPN and password.

If the account is not a Microsoft 365 work/school account (for example, Gmail, Yahoo, or another provider), contact that email provider to verify the correct password and any special app or security settings required.

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References:

• NoSuchAccountException: Login Error
• Access Denied: Login Error
• Can’t sign in to the Outlook mobile app
• An unexpected error occurred. Tag: 4oggx Code: 1864098253 - Microsoft Q&A Correlation Id:
• Cannot login to my outlook account from iphone even though details are correct - Microsoft Q&A