I do not use rss anymore but I see two items.
atom feed is in the xml file . Did you modify something to add that?
Also you are missing a language statement in the xml.
You can use
https://www.rssboard.org/rss-validator/to check.
The string should be en-us
If you open the UBB cp and then goto language files.
There are two files that should contain that
Myfeeds and generic
Look for a key name of RSS_LANG
Make sure you have en-us as a entry and re-save.
