I keep getting "Vagrant Failed to initialize at a very early stage" error when trying to set up Trellis

trellis
6

My sites are at ~/Sites

eg.
~/Sites/greatwebsite/greatwebsite.com
~/Sites/greatwebsite/greatwebsite.com/site
~/Sites/greatwebsite/greatwebsite.com/trellis

I forgot I commented here and opened a new topic here: `trellis up` gives error