Request is always invalid when using MessageBird RequestSigner

Question

I'm not sure what I've done wrong. But the requestSigner.isMatch always returns invalid request. I've used this https://github.com/messagebird/java-rest-api/blob/master/examples/src/main/java/ExampleRequestSignatureValidation.java as my reference but still same :(

public boolean isValidRequest(String signingKey, String timestamp, InputStream requestBody) throws IOException {
    RequestSigner requestSigner = new RequestSigner(messageBirdSigningKey.getBytes());

    byte[] bodyBytes = readAllBytes(requestBody);

    Request request = new Request(timestamp, "", bodyBytes);

    return requestSigner.isMatch(signingKey, request);
}

I pass an empty string for the queryParams since the incoming message has null queryParams. The messageBirdSigningKey is the signing key provided by message bird.

Any leads would be a great help!

thank you!