I have a Sonos Port with current software (uploaded on another Sonos network)

I tried to create a new Sonos network with this port on a different wifi network using my Android mobile phone with the latest App.

The Add device process kept failing at the last step to register the port on Sonos network. I could see the device on my phone in the Sonos app; it prompted me to Fix it but it kept failing telling me to try again later.

I then looked at one of the discussions and it suggested using the Sonos Windows App, which I have on my PC to manage the update. This worked. The registration step completed, and the new Sonos system is working fine, both on the Sonos app on my Windows PC and on my Android mobile phone.

As the discussion suggested, the problem seems to be the mobile phone app.