Analog Thumb Stick Problems
Physically disconnect all connections of the module from the Arduino. 
Then, check the resistance between the Vcc pin of the module and the actual pins at each end of each little potentiometer in the joystick device on the module. 
Similarly, check resistance between the Ground pin of the module and the physical pins at each end of each potentiometer in the joystick device. 
Finally check the resistance between the VRx pin and each of the center contacts of the little potentiometers, and similarly with VRy.


In a working module, in each case you should see a zero or nearly zero (~10 Ohms) resistance for one specific potentiometer pin from the module pin. 

Almost definitely the soldering of one of the device pins on the module board is not perfect - Most likely the Vcc pin to one of the X-axis potentiometer's pins won't give you the low resistance reading expected. 

Re-solder that connection on the little PCB.