Unable to get PWA projects using rest APIs

I want to get sharepoint project information using rest API's with the access token generated from a registered app. However we are running into below error when getting the projects in postman with below URL. (Which works in browser(after login) when accessed via cookie access)

Url - https://xxxxxx.sharepoint.com/sites/pwa/_api/ProjectData/[en-us]/Projects?format=json

Headers - Authorization - Bearer xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Accept - application/json;odata=verbose

Response -

{
    "error": {
        "code": "-1, System.InvalidOperationException",
        "message": {
            "lang": "en-US",
            "value": "User:<customercontent></customercontent> not found in Active directory or in project db."
        }
    }
}

Any help to get past this error would be greatly appriciated.