Please review the troubleshooting steps here before factory reseting:
Resetting your Square reader can be done as followed:
1. Minimize the SalesVu POS
2. Go to 'Settings' of your iPad
3. Go to 'Bluetooth'
4. Locate the Square reader
5. Touch on the 'i' icon and select 'Forget this device'
6. Next locate the 'power' button on your Square EMV contactless reader
7. Press and hold on the power button for 20 seconds and release the button once red lights on the reader flash off
8. Once you release the button, please wait for 10 seconds
9. Press the button again to turn the reader on and observe any lights on the reader. If the reader lights turn on, please follow the next steps. (If the lights don’t turn on, please try again)
10. Reopen the SalesVu POS -> Touch on the gear icon and 'Connect with Square'
11. Follow the on-screen instructions to re-pair the reader
12. Green lights will appear once its successfully connected