Gps singal lost
Often, when your GPS is in a "covered" area ... e.g. inside a building, in a tunnel, under a bridge, amongst / under tall buildings, etc... when there is no open space (directly) between your GPS and the satellites, your GPS will loose its satellite signals. If you're in such locations, try to find some "open space" and wait a bit for the signals to be picked up again.
Another common reason why the GPS doesn't get signals, or doesn't get the signals quickly, is because the "latest" satellite positions (locations) have not been updated in your GPS. If/when you connect your GPS to your computer (e.g. using HOME ) and download the GPS satellite (QuickFix) location information, your GPS will have the most recent locations of the satellites in your vicinity/region. With this information, your GPS can pick up the signals more quickly ... instead of having to search/scan around to find the signals ... which can take a bit more time. While your GPS is searching for the satellite signals, it shows the "signal lost" or "no GPS signal" message.