If your ‘Siemens S55’ 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” > “Setup” > “Network” > (Highlight “Auto Network” and select “Change” to disable this option) > “Choose Network” > (Wait for search to complete and choose a network)

If this resolves the issue, please change the network search mode back to “Automatic” when you travel to a new location.