Database connection "Postgres" is missing, or could not be created

Im using cakephp v2.10.24 in AWS EC2 instance (ubuntu), and i want to connect AWS RDS db in my project. In database.php file i have changed datasource from Mysql to Postgres i.e., ‘datasource’ => ‘Database/Postgres’.

But when i try to connect, im getting this error message in error log.

2021-04-13 08:48:47 Error: [MissingConnectionException] Database connection “Postgres” is missing, or could not be created.
Exception Attributes: array (
‘class’ => ‘Postgres’,
‘message’ => ‘Selected driver is not enabled’,
‘enabled’ => false,
)

Did you check in your PHP configuration, if the driver is loaded/installed?