Regarding Folders API

I have use the 'Client Credentials Grant' Authorization method to fetch access token, so using that access token i wanna get the folder data. So '123456789' This is the folder id which i want to fetch the data, the API end point which i am using is (https://api.box.com/2.0/folders/#folderId#). The error message shows "Invalid value 'd_123456789'. 'item' with value 'd_123456789' not found". But the Actual folder ID is 123456789. Can you please check on this and do the needful. Thank you.