Google API changed the rules in June 2016. Staring this date the geolocation from Google will work only over https sites.
For that reason starting version 1.16 WP Residence uses as source for geolocation info over http the with http://ipinfo.io/ API, and for https sites Google Maps Geolocation API.
For clients who use https for their site (which means adding SSL (this is done via server) – they can still use Google Geolocation. That has always been accurate.
For clients who use only http (no ssl) – the info is taken over ipinfo.io and in this case results could have a margin of error.