Quick follow-up to the previous radicale post.
It would seem that I’ve finally resolved my issues with the connection between nginx and radicale by…following the radicale documentation for a secure connection between the two, which involves explicitly adding the domain’s SSL certificate and key to the radicale location in the server block through proxy calls (if I’m understanding how this works…which I think I am…partially…).
…aaand as I was writing this the same error popped up again. Cool. Great. Wonderful!
Back to the drawing board.