Hi @wellboz, thank you for reaching out to us, and welcome to the Sonos community. I appreciate your detailed post describing the issue as well as the steps that you did. Let me help and try to figure this out.

We have identified that Asus RT-series routers blocking Sonos. Disabling the Airtime Fairness in the router settings should do the work. Getting an error “incorrect password” doesn’t mean that your WiFi password is incorrect, it just your Sonos failed to register to the wireless network. Let me suggest the next troubleshooting and see if it works for you.

• Unblocked Sonos
  • Download the Asus app on your mobile device.
  • Confirm the mobile device is connected to WiFi and launch the Asus router app.
  • Tap Devices.
  • Scroll to the blocked Sonos device and tap on it to open a new menu.
  • Disable Block Internet Access.
  • Test the Sonos app feature (connect, update, playback).
    • Note: You may need to reboot the affected Sonos players.
• Run wireless setup
  • A speaker should be wired to your router to perform this.
  • On the Sonos app, please go to Settings > System > Network > Wireless Setup.
  • You will see your WiFi network name on the list. Select it and enter your WiFi password.

After performing the steps above and you're still experiencing the same problem, please contact our Sonos Customer Care support to perform in-depth troubleshooting and understand your full network setup. Our phone support has the tools to check what's going on in your system and to remotely access your device to address the issue. 

Please feel free to reach out in the future if you have any other questions.

You're always welcome here