Sign in to OneNote for iPad or iPhone with an eligible Office 365 subscription

I'm trying to sign in, but OneNote tells me I don't have an eligible Office 365 subscription

I have a subscription: If you already have an Office 365 subscription, tap Sign In and enter the email address associated with your subscription. This might be the email that your school or work gave you.

I don't have a subscription: If you don't have an Office 365 subscription, you can sign in with a free Microsoft Account that gives you full access to OneNote (except for SharePoint access). If you don't have a Microsoft account, tap Create Account to create a free Microsoft Account.

I'm trying to activate, but OneNote tells me I don't have an eligible Office 365 subscription

I have a subscription: If you already have an Office 365 subscription, tap Sign In and enter the email address associated with your subscription. Tap Activate by Signing In to sign in with a different email address.

I don't have a subscription: If you don't have an Office 365 subscription, you can purchase one online.

Why can't I open my SharePoint notebooks?

You need to sign in with an eligible Office 365 subscription to use OneNote notebooks on SharePoint. If you already have a subscription, sign in with the email address that your work or school gave you. If you don't have an Office 365 subscription, you can purchase one online.