Refresh feed after posts deleted, does not pull second time

Greetings,

I tested the feed: http://www.mkchi.org/feed
and it loaded 10 articles.

I deleted the posts and feed and when I tried to re-establish that feed it did not pull anything anymore no matter what I did.

https://wordpress.org/plugins/cybersyn/