Sitemap files not being generated

I am using the latest version the plugin, under WordPress 3.9.1 I just noticed a few days ago that my xml & xml.gz files are quite old, dated 31-03-2014, so my sitemap doesn’t update anymore, and obviously newer posts don’t get send to Google. Neither do the new files that you mention under the new plugin.

Also if I click on the “your main sitemap and all sub-sitemaps” in the settings page, and the on the sitemap.xml, I get the following error:

Error loading stylesheet: An unknown error has occurred (805303f4)
https://bubulinagospodina.com/wp-content/plugins/google-sitemap-generator/sitemap.xsl

and if I click on the new xml’s I get:

XML Parsing Error: no element found
Location: https://www.bubulinagospodina.com/sitemap.xml
Line Number 1, Column 1:
^

I uninstalled and reinstalled the plugin (funny enough that it remembers the settings), but the problem remains. I have also tried the previous veriosn and the sitemap.xml doesn’t get updated…

https://www.ads-software.com/plugins/google-sitemap-generator/