What is the polarity of your adapter? Negative or positive tip? The 24V Qtron adapter is positive tip. If you use the wrong polarity, the best outcome is that it won’t work. The worst outcome is that you end up with an attractive door stop.
In which country do you live?
You can get the 24V 100mA USA adapter for $13.10 here:
The 24V 100mA UK adapter here for $14.80 (USD) here:
The 24 100mA European adapter here for $14.80 (USD) here:
That’s not too much really for a properly matched adapter. My experience has been that sometimes even if the voltage and amperage are close enough, the polarity might be wrong, or the plug size might be off by just enough so that it works intermittently as things get bumped around, or it’s not properly shielded so that it creates excessive hum. This isn’t a digital circuit, but just FYI. With digital circuits, it’s even more important to use original matched adapters because of other differences in the way power adapters deliver power.