Check the following:

• Either the AC adapter is connected and plugged into an electrical outlet or the batteries are installed in the printer.
  See "Power supply" for more information.
   
• The printer is turned on.
  If the LED is off, press the power button and confirm that the LED blinks in green.
   
• Your mobile device is not in sleep mode.
  If your mobile device is in sleep mode, unlock your device.
   
• Bluetooth^® on your mobile device is on.
  If Bluetooth on your device is off, turn it on.
   
• You selected the correct printer in P-touch Design&Print or Brother iPrint&Label.
  See "How can I connect my mobile device to the printer? (P-touch Design&Print / Design&Print 2)" / "How can I connect my mobile device to the printer? (Brother iPrint&Label)" for details.

  Depending on your environment or device, it may take time to connect. Wait until the message indicating the connection is complete appears on your device.

• The printer is not paired with another device.
  If your printer is paired with another device, turn the printer off and on, or turn off Bluetooth on that device, and then turn it on.
   
• The printer and your mobile device are close enough to communicate.
  If the printer and your device are far apart, locate them as close as possible.
   
• No devices that emit radio waves (for example, a microwave oven) are located nearby.
  Move the printer away from such devices.