empty replay for csrf-token

- Step1: install pulsar-manager with docker with version v0.3.0

```
docker pull apachepulsar/pulsar-manager:v0.3.0
docker run -it \
-p 9527:9527 -p 7750:7750 \
-e SPRING_CONFIGURATION_FILE=/pulsar-manager/pulsar-manager/application.properties \
apachepulsar/pulsar-manager:v0.3.0
```

- Step2: access ui with url: http://localhost:9529

-- 2.1: login in with user pulsar/pulsar
-- 2.2: login in response with: 404

- Step3: get token

-- 3.1
`curl http://localhost:7750/pulsar-manager/csrf-token
`
-- 3.2
`curl: (52) Empty reply from server
`
### Question is:
What's wrong with my steps or anything wrong with pulsar-manager v0.3.0 ?