Weird Echo Bug?

[zozo]

I've just set up a new Echo dot and it seemingly has a weird bug.  The app is able to recognize and play back the commands I give it and show the response Alexa would say .. but I get no playback sound on the device, except for streamed songs.  Asking the Echo dot simple commands like "what time is it?" get nothing verbalized back, but the correct response is on the phone app.  Has anyone else seen this one before?  Thanks.

[mike27oct]

Unplug it for 5 minutes and while off shut the Alexa app of your mobile device completely off, and restart it again a minute before you plug the Echo back in.  Now your devices are cleared of any data gremlins, and once the Echo boots up fully it will say Hello -- did it?  If not, adjust the volume to a sensible level by saying, Alexa, volume level 5.  Now, say Alexa Hello, ask it what time is it?  Working now?

Be sure to use no other power supply and power cord other than the one that came with the Echo.  Wrong parts connected to it can be fatal or at least cause misbehavior.