Google Maps needs a strong internet connection to work properly. If your internet connection is weak, it may be causing Google Maps to show your wrong location. Try moving to a location with better internet reception or connecting to a different Wi-Fi network.Google is interpreting your IP as belonging to a different country from the one you have selected due to discrepancies in IP databases. Google could also be attempting to interpret your location using methods other than your IP. The mismatched location does not suggest your VPN is not working.
