Check your database connection settings, including hostname, port, username, and password. Verify that the database server is running and accessible from your Node.js application.

Database connectivity issues in a Node.js application can be a significant hurdle, disrupting functionality and user interactions. When faced with such problems, the first step is to thoroughly check your database connection settings. This includes confirming the accuracy of the hostname, port, username, password, and database name specified in your connection string. Any typos or incorrect configurations can prevent your application from establishing a successful connection. Next, verify that the database server is actually running and accessible from the machine where your Node.js application is hosted. You can test this by attempting to connect to the database using a command-line tool or database client. Additionally, consider checking network configurations, such as firewall rules that might be blocking access to the database server. If you're using a cloud database, ensure that your Node.js application is authorized to connect; this often involves setting up security groups or IP whitelisting. If you're using connection pooling, ensure that your pool size is adequately configured to handle your application's load without overwhelming the database. By systematically addressing these potential issues, you can resolve connectivity problems and ensure your Node.js application interacts smoothly with its database.