There are so many reports in the Amazon support about the Echo Dot issues, one most common issue is the Echo Dot can’t hear your commands specially when you are playing music, the 90% of the time it can’t hear you.
We recently did a review of the Echo Dot 2nd Generation model and details all the details of pros and cons of using it.
There are number of solutions to this on Amazon.com and other support communities like online forums.
The issue appears to be only on Echo Dot 2nd Generation model, the 1st Generation model does not have that much of people reporting such issues.
The Voice Training settings seems to fix the issue. So this is how you do it.
When you setup it will typically ask you to do a Voice Training so it knows your voice an it can be heard anyway try these steps go to the Alexa app –> Settings –> Voice Training and follow the steps.