Simple API but have error. Error: Cannot find module for page: /api/auth/

[IRediTOTO]

I got this error, I worked norman before :s I don't know why

Just a simple api, it error but then it work normal as expected. I don't think I write wrong code...
And Is there post about: HOW to track error of nextjs, I got a wrong database connect but it didnt show on console, I just know it when I fetch API (status 500) and that make me hours to find it :| This is sad. I use next-connect too