JSitemap integrates third-party web services to retrieve informations about your site.

It could be the case that your site has no every kind of stats informations available, then the report will show a 'N.A' notice and no informations. Indeed SEO Stats depends on external third-party services like https://www.statscrop.com, so you can eventually request them to crawl your site.

In this case you can try switching all the third-party web services that are integrated to check if any of them have collected statistics about your domain.
If your site is not crawled by a SEO Stats services, data will not be available.