multisite category feeds

So… I would like to be able to publish feeds based on the category on my sub-sites. i.e. https://subdomain.primarydomain.com/category/article/feed

For some reason, category feeds are not working on my subdomains. In fact, if I click on the category under the individual blog post, i get a “page not found” error.

any thoughts? my main feed (subdomain.primarydomain.com/feed) works fine.

Thanks,
Matty
@otr_fat2fit