iTunes downloading some podcasts but not others
I'm using High Sierra, iTunes 12.8.3. Some podcasts are downloading fine as always. Others recently started giving me this error message: "A secure network connection could not be established. The certificate chain for this server is invalid".
My work around is to go to the podcast site, download the mp3, and add to library but this is a pain. I've also unsubscribed and resubscribed but that didn't help. Any help would be much appreciated. Thank you!
MacBook Pro 15″, macOS 10.13