Is the good nature A24 rubbish, or am I using it wrong?

I was given a couple of A24 traps to install on my property. I was very excited to try them out. I bought the lure, set them up and got ready to start clearing out rat carcasses. Alas, I have not caught a single rat with them. I have tested all functions and it seems operational. The piston is live and the lure dispenser is activated. There are rats in the area that I am catching in my conventional traps near by.
Am I doing something wrong, or is the trap design flawed? Many people on the internet appear to be getting the same disappointing results with this model trap.

One thing I’ve heard is that it’s important to get the height right for the target animal (not too high or too low), and check that the lumps and bumps of the tree trunk aren’t angling the trap subtly outwards and possibly making the animal’s forepaws lose their grip on the plastic as they climb in.
How high to set a Goodnature A24 - Goodnature NZ

Also, make sure to smear plenty of lure around on nearby trees so the animals are able to prefeed and get a good taste of the lure before they have to poke their heads into the funny-looking tube.