Error connecting to Cloud SQL from App Engine deployed Node.js app

Question

I have a Node.js backend application using Express and Sequelize, deployed on Google App Engine, and connected to a Google Cloud SQL database (MySQL). The application works fine locally when I test the API to add data in Cloud SQL Database, but after deploying to App Engine, I'm getting a SequelizeConnectionError with the message 'connect ETIMEDOUT'. This happens when I try to test CRUD operations against the Cloud SQL database from the deployed app.

Error logs screenshots

Postman error response

How can I troubleshoot and resolve this connection error when connecting to a Cloud SQL database from a Node.js app deployed on Google App Engine?

--- More ---

• The database connection configuration in dbconfig.js is correct and works locally.
• The error suggests a timeout issue, but I'm not sure what might be causing it in the deployed environment.
• I've tried deploying with different Node.js runtime versions on App Engine but still encounter the same error.
• All of the connection errors happen only when I test the API with the hosted url

Below is the code related to the database connection: [dbconfig.js] dbconfig.js

[models/index.js] models/index.js

[app.yaml]

runtime: nodejs18  # Node Version
entrypoint: node app.js

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