`NextResponse.next()` used in a Route Handler in the App Router
Why This Error Occurred​
Route Handlers in the Next.js App Router do not support using the NextResponse.next() method to forward to the next Middleware.
The Route Handler is considered the end of the middleware "chain". Handlers must always return a Response object instead.
Possible Ways to Fix It​
Remove the NextResponse.next() and replace it with a correct response handler.