How to retrieve ItemAttachment contents from Office 365 REST API?

Question

UPDATE: Many thanks to Venkat for answering this below!

The get request needs to be formatted as follows in order to retrieve the contents of a .msg

Answer 1

Yes, our documentation needs to be much clearer on how to retrieve the Item. Please try https://outlook.office365.com/api/v1.0/me/messages/{messageid}/attachments/{AttachmentId}?$expand=Microsoft.OutlookServices.ItemAttachment/Item and let me know if this works for you.