Hey,
I'm trying to automatically control my light. I have got old IR-Switches with a remote control from "Jung". As long as im using the remote control by Jung to turn on and off the light I have no issues. Now I tried to decode the signal of the remote control using an IR-Receiver. This is working fine with every remote control (like program clickers) i have (meaning i get the hex values in the Serial Monitor) except for this one remote control for the light switches where im getting no print at all meaning the irrecv.decode(&results) is false.
that is not a very good method for investigating an unknown IR signal. First, as already has been said, it may use a different modulation frequency. You can capture the IR signal before demodulation using a non-demodulated receiver, see for example my nano-project. Secondly. you are using the dated Shirriff library for with its decoder, which, even if the modulation frequency is ok, may just ignore some protocols. (An alternative to the dated IRremote library is my library "Infrared" (or Infrared4Arduino), available in the Arduino library manager.)
Staying with your demodulating receiver, try to dump the received signal in raw form with IRrecvDumpV2 (of IRremote) or IrReceiverSampler (of Infrared) and post it here.