504 Error getting messages from shared mailbox

Question

I'm trying to get a message from a shared mailbox with the graph api

curl -X GET "https://graph.microsoft.com/v1.0/me/messages/<message-id-here>/\$value" \
     -H "Authorization: Bearer <graph-api-key-here>" \
     -H "Content-Type: application/json" \
     -H "Prefer: outlook.allow-unsafe-html" \
     -v


{"error":{"code":"UnknownError","message":"","innerError":{"date":"2025-01-27T21:37:28","request-id":"fbbc7986-2d63-4a0e-a511-1a017705a043","client-request-id":"fbbc7986-2d63-4a0e-a511-1a017705a043"}}}

It takes 30 seconds for the request to complete and the error to show up. Feels like a timeout but the message I'm trying to retrieve is very small.

The same token retrieves (much larger) messages from a non-shared mailbox near instantly.

I checked the scopes and it does have the Mail.ReadWrite.Shared scope as expected.

The user getting the token has full permissions on the shared mailbox

Why am I unable to retrieve messages from the shared mailbox?

Answer 1

Hello Kaczmarek, Dan,

Thank you for reaching out to Microsoft Support!

For the mail obtained from the shared mailbox, it is expected that the mail in the shared mailbox cannot be obtained through the /me endpoint.

It is recommended that you obtain the mail according to the document and use the user_id to obtain the mail shared by the user.

Please see the link for details but be careful to ensure that the user has successfully shared the email to you.

https://learn.microsoft.com/en-us/graph/outlook-share-messages-folders

Hope this helps.

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