Suddenly unable to log into Outlook App on iPhone, company IT struggling to diagnose

Hi @Alicia C,

Thank you for reaching out to the Microsoft Q&A Forum.

To help you with the “Oops, something went wrong” error in the Outlook iOS app when signing in via Microsoft Authenticator, I recommend removing all email accounts from Outlook and clearing the credentials cache. This helps eliminate any outdated cached data that could be preventing a successful login.

First, let's reset Office apps following steps mentioned below and verify whether issue re-occurs.

1. Close all the Office apps.
2. Go to iPhone Settings.
3. In Settings, tap to select one of your Office for iPhone apps such as Word, Excel, or PowerPoint.
4. Under RESET, tap Reset<app name>**.
5. Slide to enable Delete Login Credentials.
6. Start one of your Office for iPhone apps.
7. Sign in using your Microsoft account.
8. Now exit and try opening the Office apps and verify the result.

You can also check for multiple accounts signed into iOS under Settings > Mail > Accounts and remove any old school/work accounts.

Since this is happening on your iPhone after a restore, cached credentials may still be lingering in iCloud Keychain or app data. As the next step, you should clear credentials cache on your phone. But unlike Android phones, iPhones don’t have a straightforward option to clear the app cache. The only way forward is to delete the app after signing out of every Microsoft application and reinstall it.

1. Log your Outlook account out of Outlook and other settngs.
2. Go to Settings > General > iPhone Storage.

3. Find Outlook, Word, Excel, etc....If you're using Microsoft Authenticator, delete it as well to reset any cached tokens.
4. Tap each app and choose Delete App (not just offload).

5. Restart your iPhone.
6. Reinstall the apps from the App Store.
7. Sign in again with only your work account.
8. Open Authenticator first and re-register your account if needed then open Outlook and try signing in again.

If your organization uses Intune or Conditional Access, you may also need to re-enroll your device using the Company Portal app and ensure your device is marked as compliant before Outlook will allow login.

Note: Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution. 

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this. 

Thank you for your patience and your understanding. If you have any questions, please feel free to reach out. 

I'm looking forward to your reply. 

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Hi @Alicia C,

It's wonderful news that the issue has been resolved. I truly appreciate your effort in finding a resolution. I believe that many users may encounter a similar issue, and your case could serve as a valuable reference for them.

Therefore, I would make a brief summary of this post so that other forum members could easily find useful information here:

Issue Description:

Suddenly unable to log into the Outlook app on iPhone (16 Pro Max). Initially, the user could see the inbox but was logged out immediately. Attempts to log back in resulted in a generic “Oops, something went wrong” error. Troubleshooting steps included reinstalling the app, restarting the device, updating iOS (18.7.1), and reviewing the FAQ link provided by the app.

On October 16, after 45 minutes with the company’s IT team, the same error persisted even after changing the password. The login flow briefly triggered Microsoft Authenticator but redirected instantly to the error page without completing authentication.

Later, HR confirmed that access was revoked for the user due to regulations, which explained the issue.

Assessment:

The error was not caused by device or app configuration but by an account-level restriction enforced by HR for compliance reasons. This highlights the importance of verifying account status with internal teams when troubleshooting persistent login errors.

As other users will also search for information in this community, your valuable vote will definitely help others with similar queries find the correct channel and useful information more quickly.

 If the answer is helpful, click "Accept Answer" and vote positively. If you have more questions about this answer, click "Comment".

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Hi @Alicia C,

Thanks for the response.

Just for clarification, the first step is to remove the account from apps such as Word, PowerPoint, and Excel.

The second step is to remove your Outlook account from the Mail accounts settings to clear the cache, as iPhones typically link your email account through this portal.

If you’re unable to open or use the Mail app, could you share a screenshot of it if possible? Alternatively, please provide a screenshot of the current application you use to manage your mailbox (other than the Outlook app), if you have one.

Furthermore, may I have your current email address using with this Outlook via private message to have a clearer picture of your current situation?

We can communicate with each other via private message, which will protect your personal information in case you want to share additional information related to your account and your progress with IT department. I'd love to guide you from there.

To view or send private messages, sign in to the Q&A forum using the account that posted this thread, then click Private Messages.    

Once I have a clearer understanding of your current situation, I’ll be happy to assist you with greater accuracy. Please feel free to share any additional details you believe are relevant. Screenshots are especially helpful and much appreciated.

Hi @Alicia C,

In addition to the steps I shared earlier, please clear the cache in your default browser as well. In this case, Safari is the default browser for iPhones. Follow these steps to clear the cache:

1.  Open the Settings app.
2. Scroll down and tap on “Safari.”
3. Tap “Clear History and Website Data.”
4. A pop-up message will appear, asking you to confirm the action. Tap “Clear History and Data” to proceed.

Note: This action will remove browsing history, cookies, and cached files from all devices signed into the same iCloud account.

With other browsers, the process of clearing cache varies between browsers, but generally follows a similar structure. Open the browser settings, locate the privacy and security options, and look for the “clear browsing data” or “clear cache” options. In most cases, you will be prompted to confirm your action before completing the cache clearing process. This can help if cached web tokens are interfering with login.

Once you've completed this step along with the others I recommended, it should help ensure all cached credentials are removed and allow you to log in successfully.

If the issue persists, please feel free to reach out with any additional details or observations. I’d be happy to take a closer look and assist further.

 If the answer is helpful, click "Accept Answer" and vote positively. If you have more questions about this answer, click "Comment".

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