Sonarr not connecting to rtorrent

Sonarr version (exact version): 4.0.11.2680
Mono version (if Sonarr is not running on Windows): 6.12.0.206-1
OS: Archlinux
Debug logs: Sonarr debug log - rtorrent not connecting (ex2dt1fu) - PasteCode.io

Running both on the same server, a headless device on my local network. So using “localhost”, , “RPC2” in the setup window

Description of issue: after a fresh reinstall of sonarr, rtorrent is no longer able to connect. I have the same scgi, xmlrpc set up, nothing has changed about it. I have recently updated rtorrent, but sonarr was working with the new version just fine until I reinstalled. Otherwise, sonarr is behaving normally. I also have rutorrent working so there is no problem with the xmlrpc configuration, though chatgpt tells me that’s where the problem lies.

Possibly related to rtorrent’s breaking change.