Is it not pairing with your tablet or is it stuck saying "connecting" or anything but Connected in the top bar?
I've had a few instances where a card reader won't connect after just using it that day.
Try the following to see if this fixes it:
- Close the POS app and reopen it, see if it connects
- Turn bluetooth off and back on
- Close all apps, restart the device and try again
- In the POS, go to settings, hardware, square reader, forget device and pair again
- Make sure you have the latest version of Square installed and that your tablet is compatible
Here's the help page on connecting your reader:
