Sign-in & Login Problems

How to Fix OneNote iPad Sign-In Error 2400 and Code -42002

Natalie Taylor Oct 9, 2026 869 views

Question details

The user is unable to sign in to a Microsoft 365 account on the OneNote app for iPad, receiving a specific error code despite having an updated operating system.

How to Fix OneNote iPad Sign-In Error 2400 and Code -42002

Product: Microsoft OneNote
Device & OS: iPadOS
Scenario: Attempting to log in to a Microsoft 365 school or organizational account via the OneNote iPad application.
Observed behavior: The sign-in fails and displays error 2400 along with code -42002, preventing access to notes and account features.

Before you start

Make sure you know your correct Microsoft 365 login credentials and have a stable internet connection before attempting to reset the application.

Solution 1Recommended

Verify Web Access and Reset OneNote App

Check if your account is functioning normally on the web, then clear the local app data to remove corrupted sign-in caches.

Often, sign-in errors on iPadOS are caused by outdated or corrupted authentication tokens stored locally by the app. Clearing these credentials can resolve the issue.

Test web login

Open Safari or any web browser on your iPad and go to portal.office.com to verify that you can successfully sign in to your Microsoft 365 account.

Reset OneNote settings

Open your iPad's 'Settings' app, scroll down the left pane, and tap on 'OneNote'. Tap 'Reset OneNote' and toggle on 'Delete Login Credentials'.

Restart and sign in

Restart your iPad, open the OneNote app, and attempt to sign in again with your account.

Verification Successful: If you can log into portal.office.com successfully, your account is active, confirming the issue is isolated to the iPad app.

Solution 2

Contact Your Microsoft 365 Administrator

If resetting the app does not work, the issue may be due to organizational policies or tenant-level restrictions.

Free Microsoft Office alternative

Try WPS Office for a Hassle-Free Document Experience on iPad

If Microsoft Office account issues are disrupting your workflow, WPS Office provides a free, lightweight, and user-friendly alternative. It requires no complicated tenant configurations and lets you get back to work immediately.

1. Download the app: Search for WPS Office in the Apple App Store and download the application to your iPad.
2. Open and explore: Launch WPS Office. You can start creating documents, spreadsheets, or presentations immediately without complex sign-in procedures.
3. Manage files locally: Easily open your existing Microsoft Office files stored on your iPad and edit them offline.

Seamlessly compatible with Microsoft Word, Excel, and PowerPoint formats.Lightweight app optimized for iPad, saving device storage and battery.Free to use with a familiar, easy-to-navigate user interface.View, edit, and manage local files without forced cloud sign-ins.

microsoft office alternative - wps office

Frequently Asked Questions

What causes error 2400 and code -42002 in OneNote for iPad?

This error typically occurs when the local authentication token becomes corrupted or out of sync with the Microsoft 365 servers, preventing the app from validating your credentials.

Will resetting OneNote delete my unsynced notes?

Resetting the login credentials usually does not delete local notebooks, but any completely unsynced data might be at risk. It's recommended to log into portal.office.com first to check what has successfully synced to the cloud.

How do I access portal.office.com on my iPad?

You can open Safari or Google Chrome on your iPad, type portal.office.com into the address bar, and enter your Microsoft 365 school or work email and password.

Login & Account Issues