Netcat listening but doesn't pick anything up

I am currently on the Oopsie machine in Tier 2 of Starting Point. This is the 2nd or 3rd time I try to use netcat (nc) in a machine and it listens on the port, but doesn’t pick anything up. I use the Pwnbox. In this particular machine I uploaded a php file to target website and I am trying to access it on the browser. I’ve used nc -lvnp (port 4444 and 1234), but it just stays listening with no action.

I’m not sure what I’m doing wrong.

Did you adjust the IP address in the script to the IP of your PwnBox?
You can use for example this script here