This step will force refresh the application without cache. After refreshing the application, it will load the latest version of the application.

{ "error": { "code": "", "details": "You are not authorized to perform this." } }

To resolve this, perform a Network Refresh.

Step 1: Launch Gmail and the NextGen app.

Step 2: Before attempting to log in, right-click anywhere inside the app and choose Inspect.

Step 3: Look for the Network tab, enable Disable Cache, and do a:

Step 5: Try logging in again.