Diagnosis
The Cube's Wi-Fi radio or its connection to Amazon's Alexa service is unstable, a common issue with congested 2.4GHz networks or certain router settings.
How to Fix It
Switch the Cube to your 5GHz Wi-Fi band. Go to Settings > Network > Your Network > Change Network. Select your 5GHz SSID (usually the network name with "-5G" appended). The 5GHz band is less crowded and often provides a more stable connection for the Cube's dual-band radio.
If That Didn't Work
Restart your router and modem. Then, on the Cube, go to Settings > Applications > Manage Installed Applications > Alexa > Clear Cache. Do not clear data. Re-test the microphone.
Heads Up
If you have a mesh network system, ensure the Cube isn't frequently hopping between nodes. You can try temporarily disabling the "client steering" or "band steering" feature in your router's app.