WFS210 Different readings on each channel

Hi,
just bought WFS210 1 week ago.
-I am trying to calibrate both probes using the calibration signal and what I found is that signal level goes from 3,2 V Vpp in channel 1 to 0,28 V Vpp in channel 2.
-I cannot compensate neither of the probes for channel 2. It always remains slightly curved upwards.
-I swapped probes with same result.
-In all cases I Don’t know where to clip the ground.

Am I doing something wrong? Is this result normal?

I would appreciate your comments
Kind regards