HomePod keeps asking for password

Every other day or so, I ask Siri to do something HomeKit related, and she replies, “I’m having some trouble with your account settings. Take a look at the Home app on your iPhone,” or “I can’t tell if you’re signed into your home. To troubleshoot, take a look at the Home app on your iPhone.” The first time I hear this, sure enough, the HomePod wants a password. My password hasn’t changed, but fine. I enter my password. That doesn’t fix the problem. I wait a few minutes and try again. Still not working. I restart the HomePod. Still no success. I have no difficulty telling it to play music with my Apple Music account, so it clearly has me logged in. Meanwhile, the Home app has no error messages. I can remove and reattach the HomePod, and that solves the problem, but again, this happens multiple times per week, and I have four HomePods in the house. It isn’t just one of the HomePods. Meanwhile, when I make sure the command goes through my iPad or iPhone, it’s successful. I’m frustrated.