Your feed file validates correctly. However, I noticed that you have a single tag defined for the one content item in your feed and you have not defined any Categories. You should make sure that the Developers Portal Categories page is not set to "From feed" and you have defined one or more Categories that specify the tag you've defined: "community". "From feed" implies that you have defined the channel categories within the feed file. In my opinion, "From feed" is the best way to define channel categories.
Additionally, you should use an extension of ".json" for your feed file.
FREE Windows desktop software for converting Direct Publisher channels to SceneGraph (SDK), for creating
BIF (Trick Play) files,
Roku (MRSS, JSON) feed files, and
FireTV feed files @
GitHub/rrirower.