WP Wunderground Error : Error reading XML file

On development site it works perfectly but after transferred it into a live site this is the output.

<!-- WP Wunderground Error : Error reading XML file at http://www.site-exmaple.com/auto/wui/geo/ForecastXML/index.xml?query=Lagos, Nigeria -->

What is the problem anyway? Any help? Please..

https://wordpress.org/plugins/wunderground/