I actually got the bridge 2.0 configured right. Everything was working well. But then the Siri suddenly did not work any more. I faced a constant error:
Another user already paired the HomeKit enabled bridge. Please ask the user to share his / her home kit settings in order for you to start using Siri voice control
The phillips support suggested to logout of my iCloud account and attempted to setup again. After that, it said to login to keychain. After logging back into iCloud and enabling the keychain, I got that same notification message above. Finally, I found out the solutions to get rid of the problem.
Settings --> Privacy --> Reset home kit connection --> Then Reconnect home kit again.