Failure to start with #366de2139

I'm getting odd errors on startup with a previously-working 3.0.x HEAD config: /etc/raddb/sites-enabled/control-socket[2]: No such server "(null)" _EXIT(1) CALLED src/main/process.c[4816]. Last error was: Unknown attribute "No" I'm not sure what the "no such server (null)" means. What do I need to do that I didn't before?