Related: #803756: No XML sitemaps available - There are currently no XML sitemap contexts available.
When first adding a sitemap after upgrade to 2.x, the UI shows this message at admin/settings/xmlsitemap/add -
"There are currently no XML sitemap contexts available"
[ Save ] Cancel
This is confusing to the user, because as stated in issue linked above, it's not actually an error message, and the correct action is to press "Save" which will generate a new sitemap.
Likewise, once I have a working sitemap visible at admin/settings/xmlsitemap, clicking edit on the sitemap shows the same message.
Either something has not gone right with the upgrade (plausible, and I can test this as I have a backup I can restore to a dev copy if that's helpful Dave), or the UI needs some loving there (clue me in to what's supposed to be happening and I can provide a patch to make it make sense). Or both :)