@willard.joseph26 Thanks for purchasing my book. Hope, it will help you in mastering JavaScript.

Regarding the issue you're facing, surely It's a issue with your database connection.

Make sure you have executed the scripts from server/scripts.sql file and you're connected to the bank_account database.

I just cloned my GitHub Repo. Switched to the branch section-1-using-class-components and executed the yarn start command from server as well as the project folder and verified the create user functionality through postman.

And I'm successfully able to create user using the /signup route.

So make sure you're running two yarn start commands in separate terminal, one from the project folder and other from the server folder and keep them running.

Also make sure your database server connection is up.

Follow these steps to install your postgresql database If the database is not working for you.

If the signup functionality is not working from postman, check If its working from the application by clicking on the Create account button and keep the chrome devtools console open to see If you're getting any error.

Let me know If that helps