Boost asio certificate verification failure

I am trying to write a basic TLS client and server program using nghttp2. The code works fine when verification of peer is turned off but i get the following error when verification is switched on.

error: certificate verify failed

Certificates
So i have created a self signed CA certificate and signed another certificate using the CA certificate
The certificate bundle is as follows
I have also added the CA certificate in the trusted certificates directory using
update-ca-certificates

Does openssl s_client work?
That's where i am getting stuck. openssl s_client does indeed work and i do getting verification ok message as shown here
The command is as follows openssl s_client -connect 127.0.0.1:3002
Server code

#include <iostream>
#include <nghttp2/asio_http2_server.h>

using namespace nghttp2::asio_http2;
using namespace nghttp2::asio_http2::server;

int main(int argc, char *argv[]) {
  boost::system::error_code ec;
  boost::asio::ssl::context tls(boost::asio::ssl::context::tlsv12);

  tls.use_private_key_file("ausf.pem", boost::asio::ssl::context::pem);
  tls.use_certificate_chain_file("ausf.crt");

  configure_tls_context_easy(ec, tls);

  http2 server;

  server.handle("/index.html", [](const request &req, const response &res) {
    res.write_head(200);
    res.end(file_generator("index.html"));
  });
  /*server.handle("/", [](const request &req, const response &res) {
    res.write_head(200);
    res.end("hello, world\n");
  });*/

  if (server.listen_and_serve(ec, tls, "localhost", "3002")) {
    std::cerr << "error: " << ec.message() << std::endl;
  }
}

Client Code:

#include <iostream>

#include <nghttp2/asio_http2_client.h>

using boost::asio::ip::tcp;

using namespace nghttp2::asio_http2;
using namespace nghttp2::asio_http2::client;

int main(int argc, char *argv[]) {
  boost::system::error_code ec;
  boost::asio::io_service io_service;

  boost::asio::ssl::context tls(boost::asio::ssl::context::tlsv12);
  //tls.set_default_verify_paths();
  // disabled to make development easier...
  
  tls.set_verify_mode(boost::asio::ssl::context::verify_peer);
  tls.set_default_verify_paths();
  std::string hostname = "localhost";

  configure_tls_context(ec, tls);

  // connect to localhost:3000
  session sess(io_service, tls, "localhost", "3002");

  sess.on_connect([&sess](tcp::resolver::iterator endpoint_it) {
    boost::system::error_code ec;

    auto req = sess.submit(ec, "GET", "https://localhost:3002/");

    req->on_response([&sess](const response &res) {
      std::cerr << "response received!" << std::endl;
      res.on_data([&sess](const uint8_t *data, std::size_t len) {
    std::cerr.write(reinterpret_cast<const char *>(data), len);
    std::cerr << std::endl;
      });
    });

    req->on_push([](const request &push) {
      std::cerr << "push request received!" << std::endl;
      push.on_response([](const response &res) {
    std::cerr << "push response received!" << std::endl;
    res.on_data([](const uint8_t *data, std::size_t len) {
      std::cerr.write(reinterpret_cast<const char *>(data), len);
      std::cerr << std::endl;
    });
      });
    });
  });

  sess.on_error([](const boost::system::error_code &ec) {
    std::cerr << "error: " << ec.message() << std::endl;
  });

  io_service.run();
}

How come the client code is failing to verify the certificates but openssl s_client is able to do so?
Thanks for the help.

Alright so as it turns out that since i am querying localhost, the certificate must have localhost as the common name.
So i created a new CSR with common name as localhost and got it signed by CA.
However, why does this error does not occur is openssl s_client is still a mystery to me