[SmartCrawl] Sitemap URL not working

We activated sitemap in SmartCrawl, but the reported sitemap URL (/sitemap.xml) doesn’t show a sitemap, rather, it just shows a copy of the homepage. We are hosted with WordPress.com, not sure if that is an issue. Could you please take a look and see what’s up? I had WordPress.com support and asked them if they can add the following line to the Nginx configuration file but they refused:

rewrite ^/(.*/)?sitemap.xml /wp-content/uploads/sitemap.xml last;

However, the WordPress.com support has assured me that they’d like to cooperate to ensure that your plugins are compatible with their service if you contact them. Please advise.