ProjectWebApp REST API: OAuth Authentication - ClientCredentials Grant type only

Hi All,

We are trying to read the Project Information (Flow: SAP<--->SharePointOnline) using the ProjectWebApp(PWA) REST APIs : https://domainName/sites/pwa/_api/ProjectData/Projects

for which we have registered the App in Azure Portal and then given the required permissions.

we are able to read the project information using the OAuth Grant Type: Authorization Code, where user interacts with authorization server to get the access token. But with the GrantType : Client Credentials we are NOT able to read?

Since its Server-to-Server interaction, we do not want User Auhorization code to interact.

Let us know how can we access the PWA APIs with OAuth: Client Credentials GrantType?

When we try to access with GrantType : ClientCredentials after getting the access token, we get the below error.

Kindly provide documents that can guide us how to achieve the above requirement.

API :  https://domainName/sites/pwa/_api/ProjectData/Projects

We have the below details after registering the app:

Toke URL to fetch the access token : https://login.microsoftonline.com/TenantID/tokens/OAuth/2

grant_type = client_credentials

client_id = ClientID@TenantID

client_secret = xxx

resource = resource/<domain-name>@TenantID

scope = https://localhost

Token Fetch: SuccessFull

API call: Error

Thanks

Sai