NestJS Swagger UI loads on real Android device but "Try it out" fails with CORS / Failed to fetch

I am developing a NestJS backend and testing it on a real Android device.

The Setup:

Backend IP: 192.168.1.5:3000 (MacBook)

Device: Real Android phone connected to the same Wi-Fi.

Observation: I can successfully open the Swagger documentation in the phone's browser at http://192.168.1.5:3000/api/docs.

The Problem: When I click "Try it out" for any endpoint (e.g., /auth/login) inside the Swagger UI on the phone, the request fails with the following message:

TypeError: Failed to fetch Possible reasons: CORS, Network failure, or URL scheme must be http or https

It works perfectly on the Android Emulator using http://10.0.2.2:3000.

Current main.ts CORS config:

app.enableCors({ origin: ['http://localhost:5175'], // My Vite frontend methods: ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS', 'PATCH'], allowedHeaders: ['Content-Type', 'Authorization'], credentials: true, }); await app.listen(3000, '0.0.0.0');

2. Returning Subclasses

A factory constructor can decide which specific implementation to return based on the arguments provided. This is often used in the Factory Pattern.

app.enableCors({ origin: ['http://localhost:5175'], // My Vite frontend methods: ['GET', 'POST', 'PUT', 'DELETE', 'OPTIONS', 'PATCH'], allowedHeaders: ['Content-Type', 'Authorization'], credentials: true, }); await app.listen(3000, '0.0.0.0');

Current Swagger Config:

const swaggerConfig = new DocumentBuilder() .setTitle('Liaison360 API') .addServer('http://localhost:3000', 'Local Development') .addServer('http://192.168.1.5:3000', 'Local Network') .build(); What I've tried:

Verified the phone and laptop are on the same network.

Verified the backend is listening on 0.0.0.0.

Since the Swagger HTML page loads, I know the port is not blocked by a firewall.

Why does the browser allow loading the Swagger page but block the actual API fetch requests, and how should I configure CORS in NestJS to allow this testing?