OK. So this item is now fixed. And it is a really interesting situation.
I have a eero Mesh wifi router. I had previously been using Cloudflare's 1.1.1.1 DNS service (
https://1.1.1.1/) but had disabled it on my WIFI router/network for some reason recently. I was having other tech issues unrelated to this.
When I re-enabled the 1.1.1.1 DNS on my eero Router/network, the OPDS connection between Calibre and my ebook reader Yomu worked fine.
So I believe this tells me that, as you suggested, there is some setting on my base WIFI network/app that is disabling this sort of feed/connection.
Calibre reverted the port back to :8080 so there was no conflict with the port. It was def something in my WIFI settings. Any thoughts and suggestions would be appreciated!
Thank you for your help!!!
Stephen