A smart speaker is a small computer that listens for a wake word, sends your voice to the cloud, and plays the reply. If any step in that chain breaks, the speaker appears unresponsive even though it may still light up.
Network problems are the leading cause. The speaker needs a stable internet connection to understand commands and carry them out. A weak Wi-Fi signal or a router change can leave the speaker connected but unable to reach the cloud.
Microphone muting is easy to miss. Many speakers have a physical mute button, and pressing it turns off the microphones. The lights may still work, but the speaker cannot hear anything until mute is turned off.
Account and app issues can also stop responses. If the speaker was set up under one account and the app is signed into another, commands may not reach the right device, or the device may have been removed from the account.