Dear Microsoft Support, I need to check whether I have access to my mailbox so that I can then perform certain actions in Exchange Online. I have noticed a discrepancy: When accessing mailboxes with an expired license via EWS, we receive an error immediately after attempting to retrieve the “Inbox” folder. However, when using Graph API, access to mailboxes remains functional even for accounts without a valid license. We need clarification on the following: Which API should we use to accurately check whether a mailbox has access to Exchange Online and can use EWS until we fully transition to Graph API? Is there an official list of Microsoft 365 licenses that provide access to Exchange Online? If so, can you provide guidance on how to reliably verify access to Exchange Online? Thank you for your help. Regards, Maksym

Mailbox Access Validation Using Microsoft Graph API

Maksym Marianchuk 0

Dear Microsoft Support,

I need to check whether I have access to my mailbox so that I can then perform certain actions in Exchange Online.

I have noticed a discrepancy:

When accessing mailboxes with an expired license via EWS, we receive an error immediately after attempting to retrieve the “Inbox” folder.
However, when using Graph API, access to mailboxes remains functional even for accounts without a valid license.

We need clarification on the following:

Which API should we use to accurately check whether a mailbox has access to Exchange Online and can use EWS until we fully transition to Graph API?
Is there an official list of Microsoft 365 licenses that provide access to Exchange Online? If so, can you provide guidance on how to reliably verify access to Exchange Online?

Thank you for your help.

Regards, Maksym