Microsoft Graph API - Mail

Mathew P Thomas 41

Hi Team,

I m using MS Graph API to call Mail API. I am able to get the token via postman by calling
https://login.microsoftonline.com/42a02713-284f-41e7-ba44-65bb7c8950cf/oauth2/v2.0/token

I use the token from above api to call :
https://graph.microsoft.com/v1.0/me/messages/

I get the below error:

"error": {
"code": "BadRequest",
"message": "/me request is only valid with delegated authentication flow.",
"innerError": {
"date": "2021-09-30T18:50:40",
"request-id": "f4431d06-9434e-4f1d-9434-43a763256a3b",
"client-request-id": "1e3c1d06-943f-4f1d-94334-44a7633276a3b"
}
}
}

Mathew P Thomas 41 Reputation points

2021-09-30T19:05:35.027+00:00

The permission are below:
CarlZhao-MSFT 42,611 Reputation points

2021-10-06T08:05:33.893+00:00

@Mathew P Thomas Would you please provide us with an update on the status of your issue?
Mathew P Thomas 41 Reputation points

2021-10-06T12:55:18.497+00:00

Hi Carl,
The issue is still not resolved, however one item that I have understood is its a permission issue as I am able to call the user APIs : https://graph.microsoft.com/v1.0/users/
But when I call any mail api its shoots :
"code": "BadRequest",
"message": "/me request is only valid with delegated authentication flow.",

I m working with the Sys Admins on permission settings as I don't have control on Azure portal.

Thanks
Mathew
CarlZhao-MSFT 42,611 Reputation points

2021-10-07T01:48:10.833+00:00

Hi, dear @Mathew P Thomas

Have you tried the method I provided you in the answer? This error has nothing to do with your permission, your error message has clearly stated that "/me request is only valid with delegated authentication flow." Since you are currently using a daemon-based client credential flow, so you can call the /users/{user id} endpoint, but as I said in the answer, if you call the /me endpoint, you must use the auth code flow to get the token.
Mathew P Thomas 41 Reputation points

2021-10-07T13:18:56.57+00:00

Hi Carl,

Thank you for your response appreciate it. I m going to work with admin to grant me access to use oauth code flow. Will let you know how it goes.

~Mathew
QURESHI, HABIB 1 Reputation point

2022-08-17T09:10:09.64+00:00

I am using Mail Graph api to send email. The service is registered in App registration. For a WebApp to API or API to API flow, we need to use client credential flow and to use Application type and not the delegated. So we are calling /users/{user id}. We are doing it in the C# code and using GraphClient.Users["xx"].SendMail()

After setting all of this, now getting this error: OrganizationFromTenantGuidNotFound - The tenant for tenant guid does not exist

For testing, we created a new tenant so that we have full access to the Azure AD for users and app registrations to complete our POC before applying it on our organizations. Will it work in such way or is the reason of it failing? Does it has to be associated somehow with O365 account, if yes how to do that without doing all of this in the organization's own tenant (without any rights as of now).

Thanks in advance for your support!

Accepted answer

CarlZhao-MSFT 42,611 Reputation points

2021-10-01T01:31:26.95+00:00

The error should be caused by you using the client credential flow. You are calling the /me endpoint, so you should use the delegated authentication flow with user login to obtain the token. For example, auth code flow or ROPC flow.

If an Answer is helpful, please click "Accept Answer" and upvote it.

Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.
Please sign in to rate this answer.

2 people found this answer helpful.
Mathew P Thomas 41 Reputation points

2021-10-07T16:01:47.443+00:00

Hi Carl,

Thank you very much for your assistance. Auth Code Flow did work for me and I m able to call the Mail API.

Appreciate your help on this.

Thanks
Mathew
Sign in to comment

Use comments to ask for clarification, additional information, or improvements to the question.

2 additional answers

Kat Hopkins 1 Reputation point

2022-01-12T00:55:24.607+00:00

Hi, Matthew, can you please write up what you did to get it working? I am trying to do something similar from flow to call Calendars.Read and get the same error you initially had. ANy help would be appreciated
Please sign in to rate this answer.
Mathew P Thomas 41 Reputation points

2022-01-12T02:32:46.7+00:00

The API which I was calling https://graph.microsoft.com/v1.0/me/messages
I was calling the /me/ with grantype = client credentials hence the errror message.
any endpoints with /me/ have to use granttype = authorization code or ROPC
Sign in to comment

Use comments to ask for clarification, additional information, or improvements to the question.
Kat Hopkins 1 Reputation point

2022-01-12T02:35:18.583+00:00

Thank you for that, I will see if that is what is going on with my flow.
Please sign in to rate this answer.

0 comments No comments
Sign in to comment

Use comments to ask for clarification, additional information, or improvements to the question.

Share via

Microsoft Graph API - Mail

2 additional answers

Your answer