Read the statement by Michael Teeuw here.
Pi keeps crashing
I have a fresh installation of Raspbien ( from noobs) on my pi 3b+. I have installed MM with only default modules and installed Alexa also. everything has been updated. The pi will run for a few minutes, ask Alexa a few questions then it will crash, no response what so ever. Is this too much for the pi to handle? Temperature rises to 75c +
Hello, I do not know what your problem is due to, but I recommend that you do not use NOOBS, use better only raspbian. You can download it here: https://www.raspberrypi.org/downloads/raspbian/
I recommend you the raspbian image with desktop (not the one with recommended software)