How to fix 503 Service Unavailable error for node.js in cPanel?

The error mainly occurs when the cPanel account exceeds its resource limits, or the application is not running due to a crash, failed deployment, or being stopped manually.

Step 1. Login to cPanel.

Step 2. Verify the resource limits if it is exceeding for your account. If it is Okay, then proceed with Steps 3.

Step 3. Search Setup node.js app and click on it.

Step 4. Open the application along with the terminal and switch to the source path of the application.

Step 5. Run the application using 

# npm start

  or using

  # node index.js runserver                   (Use the startup file to run the application)

Step 6. If you are experiencing an error stating that the port is already in use, verify whether another application or instance of the   Node.js server is already running on that specific port. You can use commands like

# lsof -i :3005 or  # netstat -tuln | grep 3005  to identify the process ID using the port.

Step 7. # kill -9 PID To kill the application

After completion, Restart the application and run 

# npm start