fluentd-ui does not start after fresh compile

Fresh compile on Ubuntu 20.04

Here is my output after compiling:

```
Successfully installed fluentd-ui-1.2.1
Parsing documentation for fluentd-ui-1.2.1
Parsing sources...
100% [12/12] lib/treeview.rb
Done installing documentation for fluentd-ui after 0 seconds
1 gem installed
root@opensearch:/opt/td-agent# /usr/local/bin/fluentd
fluentd fluentd-ui
root@opensearch:/opt/td-agent# /usr/local/bin/fluentd-ui setup
root@opensearch:/opt/td-agent# /usr/local/bin/fluentd-ui start
root@opensearch:/opt/td-agent#
```

Any notions on what I can check to get this started?