Azure Graph 403 Authorization\u RequestDenied使用VSTS中的服务主体

我有一个服务主体,VSTS使用它来运行Azure Powershell脚本。我要呼叫的命令是 Get-AzureRmRoleAssignment 。我收到以下错误消息

  "Exception": {
     "Request": {
       "Method": "POST",
       "RequestUri": "https://graph.windows.net/********/getObjectsByObjectIds?api-version=1.6",
       "Properties": "System.Collections.Generic.Dictionary`2[System.String,System.Object]",
       "Headers": "System.Collections.Generic.Dictionary`2[System.String,System.Collections.Generic.IEnumerable`1[System.String]]"
     },
     "Response": {
       "StatusCode": 403,
       "ReasonPhrase": "Forbidden",
       "Content": {
         "odata.error": {
           "code": "Authorization_RequestDenied",
           "message": {
             "lang": "en",
             "value": "Insufficient privileges to complete the operation."
           }
         }
       },
       "Headers": "System.Collections.Generic.Dictionary`2[System.String,System.Collections.Generic.IEnumerable`1[System.String]]"
}
}

我已验证服务主体是否具有角色分配的读取权限。