If your ‘LG GU230’ device displays a “No Service” or an “Emergency Calls” only message, this would usually indicate that you are in a location with poor signal strength / limited network coverage.
As a further test however, we would recommend attempting to select a network manually –
“Menu” > “Settings” > “Network” > “Manual” > (Phone will search) > (Choose a network)
If this resolves the issue, please change the network search mode back to ‘Automatic’ when you travel to a new location.