Most common reasons

1)Backend is blocking the request
If you’re using Node / Express / Flask:

Frontend → localhost:3000
Backend → localhost:5000
Browser throws 403

->Fix (Express)

const cors = require("cors");
app.use(cors());

->Fix (Flask)

from flask_cors import CORS
CORS(app)

Hey!

Welcome to Codespaces! A 403 error when trying to access your app usually means there's a port visibility or permissions issue. Let me walk you through some troubleshooting steps:

1. Check port visibility
   When your app starts, Codespaces should automatically detect the port and forward it. Look at the bottom panel of VS Code (in the Codespace) for a "PORTS" tab. You should see your WordPress port there (usually 80 or 8080).

If the port shows as "Private", click on it and change the visibility to "Public"
Right-click the port → Port Visibility → Public

2. Try accessing through the forwarded URL
   In that PORTS tab, you'll see a "Local Address" or "Forwarded Address" column with a URL. Try clicking on that URL directly instead of just localhost.
3. Check if WordPress is actually running
   Open a terminal in your Codespace and run:
   bashdocker ps
   This will show if your containers are actually running. If nothing shows up, you might need to start them:
   bashdocker-compose up
   (or whatever command the project documentation specifies)
4. Look at the container logs
   Sometimes the container starts but WordPress has an issue. Check the logs:
   bashdocker-compose logs
5. Check the devcontainer.json
   If the project came with a .devcontainer/devcontainer.json file, make sure the forwardPorts section includes the port WordPress is running on.
   Quick question: When you say "it does not appear in the browser" - are you clicking on a pop-up notification in Codespaces, or manually typing localhost into your browser? The localhost approach won't work since the Codespace is running on GitHub's servers, not your local machine.