HomePod 2

Both need to be in the home app, signed into the same Apple ID and both HomePod speakers need to be assigned to the same room.

1. In the Home app on your iOS or iPadOS device, tap a HomePod.
2. Scroll down, then tap .
3. Tap Create Stereo Pair and follow the onscreen instructions.

Set up a HomePod stereo pair - Apple Support

it might not be on the same wifi if you have more than one network or you’re using more than one Apple ID . Use your primary ID for all devices

You will need to reset it, then set it up again:

To Reset:

1. Unplug HomePod or unplug the power adapter for HomePod mini. Wait 10 seconds, then plug HomePod back in.
2. Wait 10 seconds, then touch your finger to the top of HomePod and hold it there.
3. The white spinning light will turn red. Keep your finger down. 
4. Siri will say that your HomePod is about to reset. When you hear three beeps, you can lift your finger.

Reset HomePod or HomePod mini - Apple Support

To Set Up:

Set up HomePod or HomePod mini - Apple Support