Please see the attached file for how to put the gantry back to being square.
Possible reasons for un-square gantry:
Improper Assembly or Loose Screws
Vibration or Movement During Operation
Worn or Damaged Rails and Bearings
Incorrect Firmware Settings
Power Loss or Abrupt Stopping
Precautions to Prevent the Gantry from Coming Out of Place:
Regularly Tighten Screws and Bolts
Ensure Proper Calibration
double check if End stops are loose/not working
Use Dampeners or Anti-Vibration Pads
Clean the Rails and Bearings Regularly