Cannot add feed from a child site to another child site

I have a multi-site install of WordPress. I am using FeedWordPress to feed post from one child site to another.

In my site https://campbell.edu/joshtate3 I am trying to add feed “https://campbell.edu/joshtate2/feed/”.

If I validate the feed via https://feedvalidator.org, it vailidates fine.
However when I try ton add the feed to the FeedWordPress plugin, I get the following error.

Diagnostic information
HTTP request failure

SSL certificate problem: unable to get local issuer certificate
HTTP Transport:

string(12) “WP_HTTP_curl”

https://www.ads-software.com/plugins/feedwordpress/