The author of GemIF pointed out that the problems experienced relate to my Gemini client, Lagrange, vs. any server issue. Now taking measures to route around this problem, i.e., search for a different desktop client.

Ariane, the Android-based client, incidentally, doesn't seem to like port number designations in supplied URIs, e.g., supplying gemini://futagoza.gamiri.com:1966 as destination results in a "Permanent Failure: proxy request refused" error whereas gemini://futagoza.gamiri.com responds fine. Could this be because I'm trying to have both share the same domain-denominated TLS cert?