Can’t verify Apple Server Notification JWT Token

I’m trying to validate an Apple Server Notification V2 (Sandbox) with a php library:
https://github.com/web-token/jwt-framework

Based on the documentation: https://web-token.spomky-labs.com/v/v2.x/the-components/signed-tokens-jws/jws-loading I thought this should do the job:

$jwt = 'eyJh...';
$jwk = JWKFactory::createFromCertificateFile('AppleRootCA-G3.cer');

$algorithmManager = new AlgorithmManager([
    new ES256(),
]);

$jwsVerifier = new JWSVerifier(
    $algorithmManager
);

$serializerManager = new JWSSerializerManager([
    new CompactSerializer(),
]);

$jws = $serializerManager->unserialize($jwt);
$isVerified = $jwsVerifier->verifyWithKey($jws, $jwk, 0);

Still it doesn’t receive a positive verification. I’ve debugged it onto this point:

$result = openssl_verify($input, $der, $pem, $this->getHashAlgorithm());

Which will give false but no content in openssl_error_string()

Any suggestions?