There seems to be a problem when the controller tries to wirelessly communicate with the Cortex. When I tether the remote to the Cortex, all the neccessary lights turn green as it should, including the Vexnet light. But when I try to connect it wirelessly using the USB things, they don't want to seem to connect. The Vexnet light on the cortex blinks orange for a little while, blinks orange at slower integer for a while, and then briefly flashes red and repeats this cycle. I have been able to establish a valid connection between the two in the past, but it only lasted for a few seconds and would not connect again. The driver control programing funtions just fine when the controller is tethered to the Cortex.
So what kind of problem is it? I have #pragma platfom(VEX) at the start of the code, which has caued issues without it. So coul it be a programming problem? What kind of code would cause wireless communications issues without having to look at the code? Or is it a hardware problem?

A few things to check...

Is your Robot > VEX Cortex Download Method set to "Download using VEXnet or USB"? If not, select it and redownload your program to transfer the setting to your Cortex.

Have you tried another set of VEXnet keys that you know work? It's possible that one or both of the keys may need to be replaced.

Have you tried connecting the 9v backup battery to help maintain the connection?