Describe the bug
I'm trying to use libssh2 on a VMware ESXi system. libssh2 was built as a static library and linked to an ESXi application. After I built and ran the example/ssh2_exec on ESXi, the call to libssh2_session_handshake failed with the error "Failure establishing SSH session: (-1) Unable to exchange encryption keys"

To Reproduce
Simply build and run the ssh2_exec example code on a VMware ESXi system. The code snippet is shown below:

    /* Create a session instance */
    session = libssh2_session_init();
    if(!session)
        return -1;

    /* tell libssh2 we want it all done non-blocking */
    libssh2_session_set_blocking(session, 0);

    /* ... start it up. This will trade welcome banners, exchange keys,
     * and setup crypto, compression, and MAC layers
     */
    while((rc = libssh2_session_handshake(session, sock)) ==
           LIBSSH2_ERROR_EAGAIN);
    if(rc) {
        char* errmsg;
        int errlen;
        int err = libssh2_session_last_error(session, &errmsg, &errlen, 0);
        fprintf(stderr, "Failure establishing SSH session: (%d) %s\n", err, errmsg);
        return -1;
    }

Run the example code, the output is:
Failure establishing SSH session: (-1) Unable to exchange encryption keys

Expected behavior
Run the same code on other Linux systems such as Ubuntu, Redhat, and CentOS. The SSH connection can be established and the remote command can be executed successfully.

Version (please complete the following information):

• local OS and version: VMware ESXi 7.0.0
• remote host OS: Any
• libssh2 version: 1.10.0
• crypto backend: OpenSSL 1.1.1q

Additional context
Because the SSH shell command works and can connect to a remote server, I assume that it's not a system configuration issue.