RSS Feed broken – 'Page Not Found'

Hi,

I’m running a multsite, with a main site at https://cubemart.com/aber/ and two test child sites at https://cubemart.com/aber/aber-reclaim/ and https://cubemart.com/aber/joes-coffee-shop/

I set up Feedwordpress RSS aggregator to aggregate content from the two test child sites on the main site. It worked for about 6 hours, and then Feedwordpress started throwing ‘Too many redirects’ and something about http_curl. I tested the following links in a browser, all of which returned ‘Page not Found’, even with all plugins disabled one by one:

https://cubemart.com/aber/?feed=rss2
https://cubemart.com/aber/feed/
https://cubemart.com/aber/feed/rss/
https://cubemart.com/aber/feed/rss2/
https://cubemart.com/aber/feed/atom/

…plus the same variants for the child sites. I noticed the error occurred after an update for Network Latest Posts plugin, which may or may not have something to do with it, but that plugin is deactivated, as are all the others.

I’m lost. What do I do next? Many thanks for your help