Lost AirPlay connection from Mac mini to HomePods 1st generation

Using Apple Music on my Mac Mini streaming airplay to my first generation HomePods. Random lost connection, and the output sound reverts to the Mac Mini headphone jack.

Mac Mini is on the same local WiFi network, and in the same room.

This happens several times a day. Especially at the end of a recording, and there is a momentary pause.

[Re-Titled by Moderator]

Original Title: Lost AirPlay connection