Fix Port Checker (PHP/JS) - Certain ports are reading closed when they are open

I have a port checker on my website, you enter an IP address and port number to scan and it tells you if the port is open or closed. I noticed that port 8000 and port 554 read closed when they are open. However there are ports that are reading perfectly, such as Port 80. I imagine this would be a simple fix, but I could be wrong.