Go to Setup and edit your General Group Profile for your RTN. Click next until you see RTN APN. Highlight the APN for your NC RTN and click the edit button (pencil). Click OK past the name of the APN. The next screen shows the RTN interface. Make sure that the communication setting matches how you are connected cellular if using the internal cell modem of the LS, or Wireless LAN if you are using a hotspot. Click next through the rest of the settings making sure that the IP address and Port are correct.