Error message: Error on line 1 at column 1

Hello,

I am getting the following error on my xml page: error on line 1 at column 1: Document is empty

Here is the URL: http://www.writechoice.co.in/writechoice/index.php?xml_sitemap=params=

I am using Hyper Cache. But the problem persists even after I deactivated the cache plugin. Please help me out here

https://wordpress.org/plugins/google-sitemap-generator/