Check your device is compatible, ensure your card reader and mobile device are charged and check your SumUp app is updated.
Reset the Air’s Bluetooth
If your device is compatible and Air is charged, but you still can't connect, try resetting your connection.
Turn your phone or tablet's Bluetooth off.
Close the SumUp app on your device.
Make sure your card reader is not charging. Then hold the reader's power button for approximately 3 seconds until it turns off.
Press and hold down the power button again until you see "Release for BT" on the display and hear a beep. Then release the power button.
Wait for a second beep and then manually reconnect your device.
Your device may be defective or blocked. Find out what to do with defective card readers.