Feed Error

I installed the plugin on my staging server and disabled all plugins except for Events Manager and Events Manager ESS. Although there’s nothing in the documentation, I assume the the feed is our domain plus /?em_ess+1. Is this correct? I did this and got the following error:

The Feed URL is not a valide ESS file: http://auroramag.staging.wpengine.com/?em_ess=1
XML Error: Extra content at the end of the document
More information about the standard: http://essfeed.org

Any suggestions?

http://wordpress.org/plugins/events-manager-ess/