How can I stop this "Not signed in...setup phone" error? I recently upgraded to Marshmallow by CyanogenMod Nightly 13.0 in my Moto E (first generation). Then I flashed GApps 6.0 Nano.
But then after my phone rebooted and I had those "Unfortunately, Setup Wizard has stopped" error. 
I fixed it by giving all permissions and rebooted again.
And then this error popped up:

Click on image for larger version



I keep on clicking on "set my phone" and this keeps popping up.

Please help me. Nothing in my phone is working.
I just had your same problem.

This is related to Google Apps: you have to enter settings -> Apps -> Google Play Services -> enable all permissions -> soft reboot.

This solved for me! Please let me know how it goes ;)