Demo DApp keeps reporting "Attempting to connect to snap..."

[FledgeXu]

Describe the bug
I'm using this Metamask beta version and try the demo DApp. However, it's not working.

Steps to reproduce (REQUIRED)
Steps to reproduce the behavior, libraries used with version number, and/or any setup information to easily reproduce:

1. Go to demo DApp
2. Click on 'Connect to Metamask'

Expected behavior
I don't know…
Screenshots

Browser details (please complete the following information):

• OS: macOS
• Brave Version 1.22.71 Chromium: 89.0.4389.114 (Official Build) (x86_64)
• MetaMask Version: 9.3.0-beta.1