I cannot log into Microsoft account from iPhone 17

Hi, Don Stouder

Welcome to Microsoft Q&A forum.

Sorry for this frustrating experience that you're facing. Here are some workarounds you can try to resolve this issue:

1) Confirm the account really exists and is typed exactly as expected

• Use Microsoft’s Sign‑in Helper. It can verify whether your email or phone number maps to a Microsoft account and point out issues. Open this on the iPhone, or on your PC if easier, and follow the prompts > Sign‑in Helper.
• If you’re unsure of the exact username, use Look up your Microsoft account from the same page. This prevents typos and helps with legacy email aliases.

If the helper says “account doesn’t exist”, the service truly isn’t seeing a Microsoft account for that identifier. In that case, try any other aliases you’ve used before (for Outlook.com, Hotmail, Live, MSN), or the phone number option inside the helper.

2) Clear stale sign‑in data on iPhone 17 (Safari and system web views)

The page in your screenshot is login.microsoftonline.com opened via Safari/system browser. Old cookies or keychain entries can cause the service to “remember” a bad identifier.

• On iPhone: Settings > Safari > Clear History and Website Data > Clear History and Data.
• Still in Settings > Safari > Advanced > Website Data > search for “microsoft” and “login.microsoftonline.com” > Remove.
• Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings (this only resets Wi‑Fi, VPN, and cellular settings; it won’t delete your data).
• Reboot the phone, then try the sign‑in page again.

3. Update Microsoft apps and iOS, then re‑add the account cleanly

• Update iOS to the newest release and update the Microsoft apps (Outlook, OneDrive, Office) from the App Store.
• Delete and reinstall the affected apps to force a fresh token flow:
  • Long‑press OneDrive, Outlook, Office > Remove App.
  • Reinstall from the App Store.
• In Outlook: Add Account > “Add an email account” > type your personal account (e.g., Hotmail/Live/Outlook.com or your non‑Microsoft address that you linked as a Microsoft account). If you see the same “username may be incorrect”, switch to the in‑app Sign‑in Helper link or try adding the account from the Outlook app first rather than Safari.

4) If you use Microsoft Authenticator, fix possible iOS keychain issues

After a phone migration, the iOS keychain can keep stale “broker” tokens that break sign‑in across apps.

• Open Microsoft Authenticator > tap the menu (≡) > Help > find Reset your accounts (available on iOS builds 6.7.12+) > read the warnings carefully > run the reset only if you rely on personal Microsoft accounts and you cannot sign in anywhere. This clears the corrupted broker cache without resetting the entire phone. Then re‑add your accounts.

This feature is designed specifically for rare iOS keychain mismatches that persist after reinstalling Authenticator, and is safer than a full device reset.

5) Try alternate sign‑in surfaces to isolate the issue

• On the iPhone, browse to account.microsoft.com and outlook.com and sign in there. If those succeed, the account is valid, and the problem is local to the app’s token flow.
• On the PC (where sign‑in works), open account.microsoft.com > Security > Advanced security options and My sign‑ins to review and update methods. Make sure your new iPhone appears as a method only if you’ve added it; remove any decommissioned devices so prompts don’t get routed to an old phone.

6) Common iPhone 17 settings that can block sign‑in

• Disable any VPN, content blockers, private DNS, or iCloud Private Relay temporarily, then retry sign‑in.
• Ensure date and time are set to Set Automatically.
• In Settings > Safari > Ensure “Block All Cookies” is off and “Prevent Cross‑Site Tracking” isn’t breaking the login flow.

7) If the service still says “account doesn’t exist”

• Re‑run the Sign‑in Helper and follow the “My username has stopped working” path. If the account truly doesn’t exist under that identifier, you’ll be guided to recovery options or to create a new Microsoft account for that address if appropriate.
• If you have multiple aliases, try the Outlook.com alias specifically. Many users who sign in fine on PC discover the mobile browser was autofilling a retired alias.

Hope this helps. Feel free to get back if you need further assistance.

Since this is a public forum, we will hide your personal identifiable information, and I have sent that image of yours containing your personal identifiable information in a private message so we can work together to resolve the issue. Also, please check your private message in case you want to share another screenshot to avoid leaking your PII by click on the Private Message button as show below.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment."    

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

I have not tried the suggestions yet. I have no problem with my iPad.