Not able to connect to azure from postman application - 403 forbidden error

I'm trying to GET https://management.azure.com/subscriptions/{subscriptionId}/resourcegroups?api-version=2020-09-01 using postman application from my desktop. For Authorization I passed the bearer token acquired from the response.

However getting the below error.

{ "error": { "code": "AuthorizationFailed", "message": "The client '02d899d6-c2d5-47d3-' with object id '02d899d6-c2d5-47d3-87b' does not have authorization to perform action 'Microsoft.Resources/subscriptions/resourcegroups/read' over scope '/subscriptions/{{subscriptionId}}' or the scope is invalid. If access was recently granted, please refresh your credentials." } }

I'm not able to find this client id in my subscription to assign the role. Where can I find this client id in the portal? Also tried to register the postman app in my subscription but the create operation is greyed out. Could anyone help on this?

I tried to reproduce the same in my environment and got below results

I registered one Azure AD application and granted API permission like below:

I generated access token via Postman using below parameters:

POST https://login.microsoftonline.com/<tenantID>/oauth2/v2.0/token

grant_type:client_credentials
client_id:<appID>
client_secret:<secret>
scope: https://management.azure.com/.default

Response:

When I used that token to list resource groups, I got same error as you like below:

GET https://management.azure.com/subscriptions/<subID>/resourcegroups?api-version=2020-09-01

Response:

The client ID in the error is the ObjectID of service principal associated with your Azure AD application having same name that can be found here:

Go to Azure Portal -> Azure Active Directory -> Enterprise Applications -> All applications -> Select Application

To resolve the error, assign Reader role to your service principal under your subscription as below:

Go to Azure Portal -> Subscriptions -> Your Subscription -> Access control (IAM) -> Add role assignment

Note that, you need to have either Owner or User Access Administrator role on your subscription to assign RBAC roles.

After assigning the role, I generated the token again and got the list of resource groups successfully like below:

GET https://management.azure.com/subscriptions/<subID>/resourcegroups?api-version=2020-09-01

Response