Ruby on Rails

Rails 5.2.1

Ruby 2.5.1

are installed 

Not able to run server for any app
What am I missing? 
rails s

Traceback (most recent call last):

2: from /usr/local/bin/rails:23:in `<main>'

1: from /Users/apple/.rvm/rubies/ruby-2.5.1/lib/ruby/site_ruby/2.5.0/rubygems.rb:308:in `activate_bin_path'

/Users/apple/.rvm/rubies/ruby-2.5.1/lib/ruby/site_ruby/2.5.0/rubygems.rb:289:in `find_spec_for_exe': can't find gem railties (>= 0.a) with executable rails (Gem::GemNotFoundException)

--
You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group.
To unsubscribe from this group and stop receiving emails from it, send an email to rubyonrails-talk+unsubscribe@googlegroups.com.
To post to this group, send email to rubyonrails-talk@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/466723b5-8539-4ffb-8bb9-a5dd0c91bd10%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.