Try resetting it.

On your iPad go to Settings/Bluetooth find your scanner and click the i and then forget device.

On you scanner hold the trigger button and the power button until you hear 3 beeps.  this unpairs it.  

Turn the scanner on and scan this barcode to factory reset it. you will hear lots of beeps and it will shut off.

Turn the scanner on and scan this barcode.

On your iPad reconnect your scanner  by going to Settings/Bluetooth and selecting the scanner once it appears.  It will then show connected and the scanner will beep.

Launch square and see if it works.