Timeout 505 on feed that seems responsive

This feed throws a Timeout 505 error in Newsblur:


Fetching the feed on my computer seems to be pretty fast, under 1 second, so this feels like a networking problem between Newsblur and that server:

$ time curl -v "https://www.scala-lang.org/feed/blog.xml" >/dev/null

< HTTP/1.1 200 OK
curl -v "https://www.scala-lang.org/feed/blog.xml" > /dev/null  0.01s user 0.01s system 6% cpu 0.454 total

Note that triggering “Fetch feed from Website” (Blog | The Scala Programming Language) also throws an error, and it shouldn’t.