Make sure you are using the correct app. For the Marksman, Hawk and LR-3 for newer phones and tablets please use the Longshot App on the Google Play Store or Longshot HD for Mac.
For the LR-2 or users with older phones or tablets, please use the Targetvision app.
Turn off the power for both the receiver and the camera.
Wait one minute then restore power.
Wait two minutes then retry connection.