Use LOAD_CELL_DIAGNOSTIC to check the function of the load cell before attempting to home or probe with it. If you see that all the values are 0, that is extremely unlikely and usually indicates some sort of wiring issue. You can tap the load cell while the diagnostic is running and you should see different results that if you do not.
I just want to VERY STRONGLY discourage you all from using those cheap HX711 boards that sample at 10SPS for probing. They are not fit for that use. They are only supported because we want to use them in weigh filament scales. Your Z axis moves a long distance in 2/10ths of a second (the default number of samples to stop is 2). This will subject the nozzle to a lot of force. (I’m considering making 80SPS the minimum for the probe and having it throw an error if you even try this. If you insist you can change the code yourself)
Also for these boards use very short wires to connect them to the MCU. Like 2 inches/5cm or less. You can use long twisted pair wires from the sensor chip to the load cell. With long leads to the chips we have seen issues with ESD rebooting the chip. These boards were never designed to be used like this.
If you must use an HX711, get the one from Spark Fun: SparkFun Load Cell Amplifier - HX711 - SEN-13879 - SparkFun Electronics
A LoveBord from Prusa is not much more money: LoveBoard | Original Prusa 3D printers directly from Josef Prusa and you get the HX717 with 320SPS.
It was actually designed to be a toolhead board with long leads. It uses an additional coms chip to make signal transmission reliable. This is what I’m using to test. More info in this thread: Load Cell Design - #37 by garethky
We for sure need to get some open source boards designed for the HX717.