Vagrant up 出错,怎么弄啊?

Administrator@PC-20170720BICL MINGW32 ~/Homestead (v7.8.0)
$ vagrant up
C:/HashiCorp/Vagrant/embedded/mingw64/lib/ruby/2.4.0/psych.rb:377:in parse': (<unknown>): could not find expected ':' while scanning a simple key at line 23 column 5 (Psych::SyntaxError) from C:/HashiCorp/Vagrant/embedded/mingw64/lib/ruby/2.4.0/psych.rb:377:inparse_stream'
from C:/HashiCorp/Vagrant/embedded/mingw64/lib/ruby/2.4.0/psych.rb:325:in parse' from C:/HashiCorp/Vagrant/embedded/mingw64/lib/ruby/2.4.0/psych.rb:252:inload'
from C:/Users/Administrator/Homestead/Vagrantfile:28:in block in <top (required)>' from C:/HashiCorp/Vagrant/embedded/gems/2.1.1/gems/vagrant-2.1.1/lib/vagrant/config/v2/loader.rb:37:inload'
from C:/HashiCorp/Vagrant/embedded/gems/2.1.1/gems/vagrant-2.1.1/lib/vagrant/config/loader.rb:126:in `block (2 levels) in load'