Starting Point 404 error

Sorry for the noob question, have made it allthe way into the enumeration phase. Have my firewall properly configured, and I am executing the RCE script. It is pinging my server port 80, but I am then getting a 404 error. What directory does shell.ps1 need to be in? Its currently just at the top at /shell.ps1. Thanks, I am close but have been banging my head over this simple fault for awhile now.

I had apache2 server already running on port 80. All I had to do was stop it using the following command:
sudo /etc/init.d/apache2 stop

Hope this helps.