Roll back to an older version of SLP to have ProPack still work (that is legacy , please find suggestions and info here and July 2016 posts here, and here in docs site . Many announcements, posts and emails were sent out over the past two years. For a year we offered discounts for those users who wanted to update. We apologize if we missed you , our record s show that your purchase is over 4 years old and you have not updated the base plugin in many years so may be missing important security patches. Basically it is suggested if you want to continue the outdated add-on, do not update the base SLP plug-in. or you may consider switching to MYSLP SAAS which is a managed software service using the Store locator Plus for a low monthly fee. You would not need to worry about maintaining and updating the SLP plug-in under our managed MYSLP service. See product and docs page for more info. If you switch over there is a way to load your locations from the current base DIY SLP to the managed SLP service
NOTE: Is your site a secured site, i.e a valid SSL cert? an https site? and do you have a valid key from the GOOGLE API developers console?
IF it is not a secure site, location sensor will not work with Chrome or the Google service regardless. Many other browsers are also adding these security measures. Google and Chrome have had restrictions since Chrome version 50 (released in 2016) and they will only return locations that are using location sensor if the request is generated within the url of a valid site (https://). See the Google developers console for more information.