I also have a similar problem and tried this command , it gives me this Output:
root@DB-Server:~# /usr/local/emhttp/plugins/controlr/controlr -port 2378 -showups
I: 2020/04/08 21:26:47 app.go:57: controlr v2020.01.11b|2.18.1 starting ...
I: 2020/04/08 21:26:47 app.go:65: No config file specified. Using app defaults ...
I: 2020/04/08 21:26:47 app.go:214: cert: found DB-Server_unraid_bundle.pem
I: 2020/04/08 21:26:47 core.go:73: starting service Core ...
I: 2020/04/08 21:26:47 core.go:271: Created ipmi sensor ...
I: 2020/04/08 21:26:47 core.go:298: No ups detected ...
2020/04/08 21:26:48 Unable to wait for process to finish: exit status 1
root@DB-Server:~#