I had posted here awhile back with issues connecting to Calibre Companion via the Wireless Connection. It was resolved, but the problem arose again one of the updates in the past few months. (I'm sorry that I can't be more specific, but it's been on going since the late summer, and I only just now had the time/internet to really investigate the issue.)
Anyhow, when I was doing some digging today, I noticed that the Calibre program is now listed TWICE in my Windows Firewall for "allowed/disallowed programs." (
link to screenshot) The bottom ones were not checked when I looked today, and checking those as well resolved my issue.
Minor bug that's easily resolved, but I wanted to share in case anyone else was having the same issue.