Category Feed Shows Error

I have a category named ‘Journal’ and I want to make it possible for people to subscribe it through RSS feed.

But the feed ( https://enwil.com/category/journals/feed/ ) shows this error:

This page contains the following errors:

error on line 21 at column 21: Specification mandate value for attribute itemscope
Below is a rendering of the page up to the first error.

Enwil ? Journals https://enwil.com Practical Philosophy Advice Sat, 28 Dec 2013 08:12:55 +0000 en-US hourly 1 https://www.ads-software.com/?v=3.8