CryptoLens

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Troubleshooting ​

Find solutions to common issues encountered while setting up, running, or developing CryptoLens.

🔌 Connection Errors between Phone and Local Server ​

The Issue ​

You start the Expo development server, scan the QR code, but the app fails to load or hangs forever at 0% or shows a network request timeout error.

How to Fix ​

  1. Match Local Network: Ensure your mobile device and your computer are connected to the exact same Wi-Fi network.
  2. Find Your Computer's Real IP: Do not use localhost or 127.0.0.1 in your frontend .env file. These loop back to the mobile phone itself. Find your machine's private LAN IP (e.g. 192.168.1.50 on macOS/Linux via ifconfig or ip a, or ipconfig on Windows).
  3. Bind Wrangler Correctly: When running the wrangler server, run it with --ip 0.0.0.0 so it accepts connections from external LAN devices, not just your local machine:
    bash
    bunx wrangler dev --ip 0.0.0.0
  4. Firewall Block: Check if your computer's firewall is blocking incoming connections on port 8787 (the worker) or 8081 (Metro). Temporarily disable the firewall or add rules to allow traffic on these ports.

🚫 Regional API Failures (Binance API) ​

The Issue ​

The app loads and the interface shows up, but you see errors like Network request failed or no charts and price updates load.

Why it Happens ​

CryptoLens streams live prices directly from the Binance WebSockets API. Binance blocks access from certain jurisdictions, including the United States.

How to Fix ​

  • Use a VPN: Connect your mobile device (or development machine if testing on a simulator) to a VPN location where Binance operates (such as Europe or Asia).
  • Check Status Codes: If you see a 451 Unavailable For Legal Reasons status, this confirms a geo-block is active.

🧹 Clearing Expo Cache ​

The Issue ​

You modified .env variables or updated React Native packages, but the app is still behaving as if it has old configurations.

How to Fix ​

Clear the cache of both Bun and Expo to force-reload the environment variables:

bash
# Start Expo and clear the cache
bun expo start --clear

📦 Missing Native Modules ​

If you get errors about missing native dependencies (such as Reanimated or Safe Area Context), reinstall compatible package versions:

bash
npx expo install --fix