The X axis moves only one direction only, no matter under AUTO or JOG mode, Z axis and other functions are fine.

Check below:

1-      Are the control cables from CNC controller to the AC servo driver loosed or opened?

2-      The control board of the AC servo driver is broken or not?

3-      Any parameter setting mistakes?

4-      Check the X axis forward and backward key on the CNC controller under DIANOSE mode, and see if there is any changes?

5-      The mechanical part is slipping or not?

In this case it is control board problem, change it then the CNC machine resumed.