I have a HomePod which was connected to old Wi-Fi and phone. I tried to set it up on new phone and did remove. Not cannot connect

Ah, see Identify status lights on HomePod - Apple Support. In particular:

Orange flashing light

HomePod mini is connected to a computer, or is plugged into a power adapter that didn't come with HomePod mini and isn't rated 20W (9V ⎓ 2.22A).

Make sure you are using the original 20W rated adaptor.

tt2

See the Press the top of HomePod to reset it section of Reset HomePod - Apple Support and follow the steps carefully as given.

tt2

You're welcome. 🙂

tt2