Setting up ZeroTier…error following documentation

The zerotier1 interface is part of (or belonging to or slave to) the bridge named “local”.
It should be “self-standing” (out of the bridge), otherwise the /ip firewall filter rules will never get used.
No idea how or why it was made part of the bridge, but maybe you are setting everything bridged, so you don’t need at all those rules.

Again, it is difficult to give advice without seeing the whole configuration, but I believe you should take your time reading this:
http://forum.mikrotik.com/t/zerotier-on-mikrotik-a-rosetta-stone-v7-1-1/155978/1

The Mikrotik instructions you probably referred to:
https://help.mikrotik.com/docs/display/ROS/ZeroTier
(like usually) work like this:

  1. you can do (say) 127 things with this
  2. here is some technobabble describing the stuff
  3. here is a (hardly useful) video
  4. here are the (vague) instructions for 1 of the 127 different possible configurations
  5. (unwritten) we leave the other 126 configurations as an exercise for the reader
  6. done