Protocol message contained an invalid tag 0

My goal is to create a realtime service alert feed and send it over to a server that I made in Java with an HTTP post request. The first step I did was to create a copy of the example alert feed posted here and it seems I was successfully able to do that as I was able to print it out the message. https://developers.google.com/transit/gtfs-realtime/examples/alerts

The next step that I did is to create an HTTP connection and send the feed over with the POST request. This is what I have in my client code and example here is the feed name.

String url = "https://localhost:8080";
URL obj = new URL(url);
HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();
//add reuqest header
con.setRequestMethod("POST");
con.setRequestProperty("User-Agent", "Mozilla/5.0");
con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
con.setRequestProperty("Content-Type", "application/x-protobuf");
con.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(con.getOutputStream());
example.build().writeDelimitedTo(wr);
wr.flush();
wr.close();

My server code is simply this so far.

ServerSocket server = new ServerSocket(8080); 
System.out.println("Listening for connection on port 8080 ...."); 
while (true) { 
    try (Socket socket = server.accept()) {
      FeedMessage feed = FeedMessage.parseDelimitedFrom(socket.getInputStream());
      Date today = new Date(); 
      String httpResponse = "HTTP/1.1 200 OKrnrn" + today; 
      socket.getOutputStream().write(httpResponse.getBytes("UTF-8")); 
      }     
} 

The question here is that I get the Protocol message contained an invalid tag 0 on the server side. I would like some help on trying to resolve this issue. Maybe I am not parsing it correctly.