No le ha dicho a su archivo de base de datos que use SSL.
<?php
$url = parse_url(getenv("DATABASE_URL"));
$host = $url["host"];
$username = $url["user"];
$password = $url["pass"];
$database = substr($url["path"], 1);
return [
'default' => 'mysql',
'connections' => [
'mysql' => [
'driver' => 'mysql',
'port' => '3306',
'host' => $host,
'database' => $database,
'username' => $username,
'password' => $password,
'charset' => 'utf8mb4',
'collation' => 'utf8mb4_unicode_ci',
'prefix' => '',
'strict' => true,
'engine' => null,
'options' => array(
"sslmode" => "require",
"sslrootcert" => "config/amazon-rds-ca-cert.pem"
)
],
