HOWTO read Outlook custom property set with GRAPH

问题

I am using the Office.js CustomProperties interface to store application specific data. Using the Office.js library I can succesfully read the information back in different application sessions using Office.js.

A different API process needs to read this data using the MS Graph interface. I did read Get custom property set in Outlook Add-In via Microsoft Graph but for me it does not work. I do get the message information but without any extended properties.

What is it that I am doing wrong? After putting a lot of time in this problem any help is so welcome...

Thanks in advance,

Wilco

来源：https://stackoverflow.com/questions/54073136/howto-read-outlook-custom-property-set-with-graph