There are three options that you can check before contacting to NanoEntek.
(1) Pipette setting is not 35μL. The incorrect volume will cause the loading issue on pretreatment tube.
(2) Please load the sample at the bottom of pretreatment tube. Less volume of sample will be loaded, if the sample remains on the tube wall.
(3) This is when the device does not operate normally due to contaminants attached to the AP sensor. In this case, cleaning the AP sensor is necessary.
Check the link below to see how to clean your AP