I had a similar problem where the rss feed no longer responds to any updates. I noticed that when I click on the link, my wordpress directory that I called blog would change to wordpress. For example,
https://www.mysite.com/blog/?feed=rss2 would change to https://www.mysite.com/wordpress/?feed=rss2 and would not find the page. When I changed the script to use rss instead of rss2 at the end it started to work again. Hope this helps.
