Error with OpenSearch

[eostis]

Hi,

I'm using the same code to add credentials for ES and OpenSearch.
It works great for ES, but fails with OpenSearch:
{“message”:”Authorization header requires ‘Credential’ parameter. Authorization header requires ‘Signature’ parameter. Authorization header requires ‘SignedHeaders’ parameter. Authorization header requires existence of either a ‘X-Amz-Date’ or a ‘Date’ header.}

$provider = CredentialProvider::fromCredentials(
new Credentials( $config['aws_access_key_id'], $config['aws_secret_access_key'] )
);
$handler  = new ElasticsearchPhpHandler( $config['aws_region'], $provider );
$client->setHandler( $handler );

Would you have an idea?