Fetching with id returns nothing

Hello, I'm wondering what I'm doing wrong, I want to GET a model by its id.

Doing http://localhost:3000/model correctly returns all model but when I call GET 
http://localhost:3000/model/521bd88c08b986f811000004 it prompts "Cannot GET...".

Could it be related to app.use('',...) instead of app.use('rest',...)?
