X axis locks tight when homing / reaching machine zero

I recently bought a M.1000 machine with Semi Closed Loop-System and finally got to try it out.

When homing the machine, the Z and Y axis homes like a charm, but once the gantry reaches within the last few cm of the X axis, the gantry gets stuck and it is impossible to move it from the software.
Pushing the emergency stop releases the automatic hold on the stepping motors, but the gantry is still stuck.
Removing the panels and covers reveals that the spindles are shaped like a bow in both sides. Loosening the stepping motors allows the spindle to return to normal and the gantry can be moved again, however fastening the stepping motors is impossible until the gantry is at least 20 cm from home.

Is this a normal problem? - and how do I come about it?
Can the stepping motors be installed wrong? - The wires are attached from within the control-compartment.

Adjusting the screws on the gantry is a possibility, but leads to a wobbling gantry with significant precision issues + the screws will come loose in the middle of even small projects.