Troubleshooting the zeus gem
First, try to run a regular command like
rails s or
bundle exec rake to see if there any issues with Rails itself and not zeus.
If the issue is clearly with zeus and for the
open /dev/ptmx: device not configured error do a:
$ sudo killall -9 ruby $ zeus start
One time I just had to kill a console window where I was running the zeus. Next, I started a new console window and then ran