上传文件，无法预览和下载，如课程图片等

[laozhou0731]

Describe the bug

A clear and concise description of what the bug is.

改善： 需要修改配置文件，将默认的 example.canvas.com 改成 域名 或 IP

Deployment method

• [ ] subscription image from MarketPlace of Cloud
• [ ] All-in-one Installer
• [ ] ansible-playbook cli
• [ ] mcloud
• [ ] create instance from private image

Bug source

• [ ] Bugs from installation
• [ ] Bugs from first use
• [ ] Other (You should describe it)

System Environment

Application Version

e.g v4.5

OS

• [ ] Ubuntu18.x
• [ ] Ubuntu20.x
• [ ] CentOS7.x
• [ ] CentOS8.x
• [ ] AmazonLinux2
• [ ] OracleLinux7.8
• [ ] OracleLinux8.2
• [ ] Other (You should describe it)

Cloud PlatForm

• [ ] Azure
• [ ] Aws
• [ ] 阿里云
• [ ] 腾讯云
• [ ] 华为云
• [ ] AlibabaCloud
• [ ] HUWEICloud
• [ ] Other (You should describe it)

Bug reproduce

Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Bug reports

Bug Context

Bug context includes bug error, error logs and service status, it is very important for resolving issue

# bug error
(paste here) 

# service status 
(paste here) 

# error logs
(paste here) 

Bug Screenshot

paste screenshot here

Your suggestion

The reason of Bug

You can describe the reason if you have found it

Your solution for Bug

You can describe your solution here

Additional context

You can add any other context about the problem here.