Youtube-dl is returning errors when grabbing from Mixcloud
I ran into the same error (2010 MacBook Pro) and updating to Python 2.7.18 seemed to fix the issue. You can update to 2.7.18 here. I used the macOs 64-bit Installer, but feel free to install whichever way is easiest for you.

Screenshot of running youtube-dl post update:


Hope this helps!