The error message "LAT/LNG Fetch Failed" appears when import tool fails to fetch the coordinates of the provided address. There are a couple of things which can be the reason for this error message, first make sure the columns "State", "City", and "Zipcode" is provided for that address, if any of these columns are missing it will surely fail to fetch the coordinates due to validation. The second thing is we are using Google Geocoding service free API which has usage Limit per second as well as per day. The limit of the service is as follows.
If you have too many records to fetch, then there are two ways to do it, either Enable Billing and use your API Key, by clicking on "Use API Key" Option.
The second way is to upload your records in chunks of 200 records each import file, but still per day limit will apply on it and you can't fetch more than 2500 records per day.
To get the coordinate values, leave the Longitude and Latitude columns empty, the store locator import tool will fetch those values from Google API using the provided address. API has Usage Limit Per Second, too many records may be blocked by Google Service.