some troubleshooting methods at the beginning, FYI

[TowerLeon]

1. stop and disable firewalld while creating new virtual machines.

[root@localhost data]# sudo systemctl stop firewalld
[root@localhost data]# sudo systemctl disable firewalld

2. create mysql users and databases as required.
   CREATE DATABASE 'sysbase';
   CREATE USER 'sysbase'@localhost IDENTIFIED BY 'SttA35BBx5dbl1xB7NS7';
   GRANT ALL PRIVILEGES ON . TO 'sysbase'@localhost IDENTIFIED BY 'SttA35BBx5dbl1xB7NS7';
   FLUSH PRIVILEGES;

3. change host as required.
   window.CONFIG = {
   apiHost: 'http://localhost:8081/',
   perPage: 20,
   }