Non-xml feed (552) error for Oxford Academic RSS feeds

I’m having trouble with the following feeds from Oxford Academic:

https://academic.oup.com/rss/site_5591/3464.xml
https://academic.oup.com/rss/site_5592/3465.xml

The parsing error for both is “Non-xml feed (552)”. However, both validate with the W3C Feed Validator. (I would link these results as well but cannot do so as a new user.)

Is there some way to get these feeds to work with Newsblur? Thank you in advance.