Your HAProxy server seems to be up, but it is not working. You use nmap or a PowerShell port testing program (see "Using PowerShell Version 3, How Do You Determine If a Port Is Open for a given IP Address?"). You find that there is activity on port 80 and/or the traffic is not blocked over port 80. But when you open a web browser, you get "File not found" or "The site cannot be reached." What do you need to do?
Possible Solution #1
Start the HAProxy service (if it was not already started). Use this command: sudo /etc/init.d/haproxy restart
Possible Solution #2
Is traffic blocked from your HAProxy server? Verify you have connectivity from your HAProxy server to your webserver(s). The port is determined in the haproxy.cfg file (e.g., 5001 or 80).