cURL error 60

Since yesterday I’ve been getting cURL errors on certain feeds. This is likely due to Let’s Encrypt’s certificate change.

Is this a problem with the plug-in code, my website hosting, or the third party feeds I am fetching? Just need to know what to do to fix this.

The sites I am syndicating which have this problem include Letterboxd, world.hey.com and feedmyride.net. A site which does not seem to have a problem as far as I can tell is goodreads.com

Thanks! Here is the error text:

WP HTTP Error: cURL error 60: SSL certificate problem: certificate has expired