When I was trying to format the citation, Paperpile plug-in asked me to authorize to continue. When all the authorization process were done, It showed authorization complete. However, when I clicked format, it went back to ask for authorization again.
This is a result of being logged into multiple Google accounts and the formatting script being repeatedly routed to the wrong account. Unfortunately, Google gives us no control over the routing, so if you encounter this, the solution is to ensure that you are only signed in to one Google account (per Chrome profile).