Tenant does not have a SPO license

In case anyone else has a similar issue, I was getting the same error message when using an Office 365 Home license. It turns out SPO stands for SharePoint Online, and you need an Office 365 Business account to have it. So as far as I can tell, you can't use the Microsoft Graph API to access OneDrive without having SharePoint (which only comes with the business licenses). This isn't really made clear anywhere that I could find.

Answering a couple of things here.

Background: Microsoft Graph is the developer gateway or API to many Microsoft cloud services, like Office 365, Azure Active Directory, EMS (Enterprise Mobility Suite), personal Outlook, personal OneDrive and more. Use of the API is free, but to access the data behind it, you need to actually have those services - in some cases they may be free and in other cases you may need to pay for them.

As for adding Office 365 to your existing tenant. I believe you've signed up for Azure using a Microsoft Account. This means that you already have an Azure Active Directory tenant. You can still purchase/acquire Office 365 for that tenant. All you need to do is create a new Azure AD user (not a Microsoft Account) in your tenant, and make them a company admin. Then you should be able to sign-up for Office 365 - if it asks if you already have a tenant or account, sign in with the AAD account you just created. And voila, you should have an Azure AD tenant with a subscription to Azure AND now a subscription to Office 365.

Hope this helps,