Hi Corbella,
We'd be happy to help with your Apple Music and Siri conundrum.
You mentioned that Siri works for other requests, just not Apple Music. Does Apple Music play on your HomePod when you hand off audio or play directly from your other devices? These instructions from Play audio on HomePod using an iOS or iPadOS device will help confirm your Apple Music subscription works as expected as well as test functionality:
Control HomePod from Apple Music or Apple Podcasts
1. Open the Music or Podcasts app on your iOS or iPadOS device, then tap the playback controls.
2. Tap
, then select your HomePod.
Hand off audio to HomePod
1. On your iPhone, go to Settings > General > AirPlay & Handoff, then make sure Transfer to HomePod is turned on.
2. Hold your iPhone near the top of HomePod.
To move audio from HomePod to your iOS device, hold your iPhone near the top of HomePod. On iPhone 11 and iPhone 12 models, hold your iPhone near the top of HomePod, then tap Transfer to iPhone.
It's also possible your HomePod is having a difficult time keeping a strong and steady network connection. You can follow If HomePod or HomePod mini isn't responding to the "Check your Wi-Fi connection" section for guidance to check your connection.
Check your Wi-Fi connection
HomePod and HomePod mini automatically connect to the same Wi-Fi network as your iPhone or iPad. To check your Wi-Fi signal strength:
1. Open the Home app on your iPhone, iPad, or Mac.
2. Tap or click HomePod.
3. Scroll down, or tap or click the Settings icon
and scroll down to Wi-Fi Network. The Wi-Fi signal strength indicator
appears next to your network name.

If the signal strength indicator shows two bars or fewer, your Wi-Fi signal strength is weak. Try moving your HomePod speaker closer to your router and remove potential sources of wireless interference.
If the signal strength indicator shows an exclamation point, learn what to do.
We look forward to learning the results of your troubleshooting.
Warmest Wishes.