"operation not permitted" when trying to use the CLI

I'm getting this error (with debugging enabled in config.yml), not sure if it's something with my networking setup or whatnot (running from a [docker container](https://github.com/snaekobbi/system/blob/release/1.8.0/Dockerfile)):

```
root@f803e6c93491:~# dp2 help
link.go:65: Initialising link
client.go:198: Get http://localhost:8181/ws/alive: dial tcp 127.0.0.1:8181: operation not permitted
Error:
Could not connect to the webservice and I'm not configured to start one
Error: Get http://localhost:8181/ws/alive: dial tcp 127.0.0.1:8181: operation not permitted
```

The version I'm using is the one bundled in the released [pipeline2-1.9-webui_linux.zip](https://github.com/daisy/pipeline-assembly/releases/download/v1.9/pipeline2-1.9-webui_linux.zip).

curl'ing the engine gives a response, so the engine is up:

```
root@f803e6c93491:~# curl localhost:8181/ws/alive

```

Has anyone else experienced this problem?