rds connection iam role mysql database

Question

Basically I'm having an issue with IAM roles and connecting to a RDS MySQL database using PHP and PDO as the connection method;

I'm going to leave out alot of information for simplicity; Lets assume I have created the IAM role correctly and assigned it correct.

Here is the error I'm getting ( Very Generic I know )

"db_connection": {
    "error": "Database connection failed",
    "message": "SQLSTATE[HY000] [1045] Access denied for user 'jane_doe'@'****' (using password: NO)"
},

Here is the connection credentials im passing;

"connection_credentials_debug": {
    "host": "****",
    "port": "3306",
    "dbname": "data",
    "dbUsername": "jane_doe",
    "authToken": "Action=connect&DBUser=jane_doe&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=ASIATQTFLNFMMISRAKAT%2F20230803%2Feu-west-2%2Frds-db%2Faws4_request&X-Amz-Date=20230803T014513Z&X-Amz-SignedHeaders=&X-Amz-Expires=900&X-Amz-Signature=ab6498cd78a0158c1bf0adcc2a482152cb7dba944cd6147d20ad396a6b22c419"
}

I think the issue is with the authToken; I think I need to do something with that auth token before I pass it or it could be a issue with the placement of the auth token in the pdo connect.

Here is the code I'm using;

    $generator = new AuthTokenGenerator(new Aws\Credentials\Credentials(
        '****', // AWS access key
        '****'  // AWS secret key
    ));
    
    $dbHostname = '****'; 
    $region = 'eu-west-2';
    $dbUsername = 'jane_doe';
    
    $authToken = $generator->createToken($dbHostname, $region, $dbUsername);

   try {
        $dbConnection = new PDO("mysql:host={$dbHostname};port=3306;dbname=data", $dbUsername, $authToken);

        // Database connection successful
        $response = "Database connection successful";
    } catch (PDOException $e) {
        // Database connection failed
        $response = [
            'error' => 'Database connection failed',
            'message' => $e->getMessage(),
        ];
    }

I am looking for a successful connection.