When responding to a request from Google Earth (or any Earth browser), a KML server must follow a certain set of rules so that Google Earth can correctly interpret its responses. Upon success, the server must return a response code of HTTP 200 and set the response's content-type to a suitable MIME type, as described here. Google Earth reads KML and KMZ files. The MIME type for KML files is application/vnd.google-earth.kml+xml The MIME type for KMZ files is application/vnd.google-earth.kmz For Apache, add these lines to the httpd.conf file: AddType application/vnd.google-earth.kml+xml .kml AddType application/vnd.google-earth.kmz .kmz See the Microsoft documentation for details on setting up MIME types on Microsoft's IIS. The body of the response must contain valid KML data, including the XML declaration (<?xml version="1.0" encoding="UTF-8"?>). If the server returns invalid KML, the Network Link will stop, deactivate, and output an error message.