MS Graph API not Working in Custom Applicaton but works in Graph Explorer

Priyadarshinee, Arpita (external) 21 Reputation points
2021-02-24T09:47:23.647+00:00

We have been trying to use ‘Microsoft Graph API’ in our application, which has stopped working since DEC 2020.
We have a Hybrid mail box setup.

While we are able to use the Rest APIs in Graph explorer (MS official Site), not working from our custom applications neither in POSTMAN and displays the following error.
"{"error":{"code":"MailboxNotEnabledForRESTAPI","message":"REST API is not yet supported for this mailbox."}}".

We have tried every AAD flow available thorugh PostMan but no success. But Graph explorer works fine from PostMan as well.

Again we have compared the token generated by both Graph explorer and out custom application in jwt.ms as well, it is also the same.

Can you please suggest if we are missing anything else ?
How can only graph explorer can access to these mail boxes, but our custom application can not ?

Regards,
Arpita

Microsoft Graph
Microsoft Graph
A Microsoft programmability model that exposes REST APIs and client libraries to access data on Microsoft 365 services.
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  1. Andy David - MVP 142.2K Reputation points MVP
    2021-02-27T14:47:18.987+00:00

    I would open a ticket with 365 support. Technically, its still in preview for hybrid:
    https://learn.microsoft.com/en-us/graph/hybrid-rest-support

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