Y-axis loosing steps

same problem, reasembled the machine all clean greased ,,,same problem , moves an 1 m p minute
and looses steps with no spindle ,, its a construction defect , sorry but not satisfied with the product

Did you guys try this 'STEPCRAFT - Y Axis Alignment' video (online since 2017 only ^^):
https://www.youtube.com/watch?v=KDuogPSI5tw&feature=youtu.be

Me i try following the debug steps, but I am stuck at the 4min mark of the video. Indeed, when I unscrew the M6 and M5 screw:
- I can achieve "vertical movement" on the front plate.
- I can I can achieve a very small "vertical movement" on the left side of the rear plate.
- But I can NOT achieve "vertical movement" on the right side (the stepper motor side) of the back plate of the CNC...

I try unscrewing the bolts of the belt, but it still didn't work.

I try unscrewing the M5 and M6 a lot. I could achive achieve "horizontal movement" (which means I unscrewed too much) but still no "vertical movement" possible on the stepper motor side of the back plate...

Any insights?