apache-pulsar-manager-0.3.0 Management menu always return 404

**Description:**
When I click the Management menu on the top menu bar, It always return 404 page.

**environment:**
1. apache-pulsar-manager version is 0.3.0,
2. JDK
openjdk version "11.0.2" 2019-01-15
OpenJDK Runtime Environment 18.9 (build 11.0.2+9)
3. OS: Red Hat 8.2.1-3

**scenario:**

then always direct to this url, http://ip:7750/ui/index.html#/404