HomePod 1st Gen, configuring

I have two HomePods (both are 1st gen). I cannot set up the two HomePods at the same time within my home app. The other one, whichever is set up later, is stuck at configuring (saying that HomePod will being configured. Additional settings will be available shortly). Even it indicated during the set-up process that the HomePod is ready, when I try to airplay it shows "Unable to connect to" it. I tried restarting it, remove the home and set everything all up again. Still there is only one that will be able to finish the process and able to function. The other one always gets stuck at configuring. The software version is 17.6 (21M71). Could I please get some help? Many thanks!!!