If you review the LA 55 datasheet, you'll realize that only the third circuit can work at all. The burden resistor (Rm in the datasheet) should have a value in the specified range. A larger value is possible if you are not utilizing the full LA 55 range (as in your test, where you are loading the sensor with 4*5 A while the range is 50 A.
The output signal must be aquired across the burden resistor (it can't be clearly seen if you connected the probe ground correctly). If it still doesn't work, the sensor might be defective.