I've been dealing with this same issue today running a VPS on sdf with their start script and configuration - I am also using their verison of drawterm.  Drawterm on ParrotOS, 9Front on SDF VPS. Same error as the poster from draw term, and confirming the reply, on the server I saw : cpu: encrypt: unknown device in # filename - tried both their start script and this method: http://sdf.org/?tutorials/VPS_Plan9 - had no idea this was the issue until I found this post, have been on IRC all day asking about it.  Will also reach out on the 9Front list as suggested.