How to request refresh token from SharePoint in Appian?

Hi there,

I am trying to connect to SharePoint from Appian. I am using Connected System. Authorization was successful but no refresh token was obtained which means users have to authorize more frequently. However, when I used this Connected System in an Integration where I am trying to upload a document, I am getting "The external system understood the request but refused to authorize it HTTP/1.1 403 FORBIDDEN" error. Please see below. 

Thanks in advance.