Can't save stream properties

[theo]

Hi, I'm test-driving minimserver and wanted to look at minimstreamer. I got a trial license and it's installed. Running all of it in a docker container. But for whatever reason I can't save streamer properties. I wanted to add the path to ffmpeg like /opt/minimserver/opt/bin/ffmpeg (I got version 6.1.1-3ubuntu5+esm10) and a transcode property as well. It doesn't let me save it. What am I missing?

Thanks guys, most likely a stupid newbie thing.