When I use a floodlight. I power it correctly, I hook it up to the wires correctly. But no matter how hard I try, that floodlight emits no light at all. I have tried to get this floodlight to work in many servers, I have tried to get it to work on another Minecraft installation. Still, I have no response of light from the floodlight.

And you also ignored the issue template.

Without version info and a debug crash, there is basically no way to help you. So please hold down F3 and C for 10 seconds, take that crashlog, put it on pastebin and link it here.
Thank you.

Oh also, there doesn't appear to be a redstone signal on that floodlight. It might be helpful if you took some screenshots of a test setup outside, so we can actually see what you are doing.