Stopped working

This used to work great but now the retriever either just keeps spinning forever, or it says invalid rss. I have run it through a validator – it’s fine – and I have also (1) cleared my cache and (2) installed the transient deleter plugin. Neither one made any difference.

[wp_rss_retriever url="https://feeds.feedblitz.com/motdujour" items="1" excerpt="none" read_more="false" credits="false" new_window="false" thumbnail="false" source="false" date="false" cache="2 hours"]

The page I need help with: [log in to see the link]