400 invalid_grant error once, works fine after that

Hi,

I'm building my simple app associated with Box API. It is built on Ruby and Rails and Boxr as Ruby client library for Box Content API. https://github.com/cburnette/boxr

It works pefect on my Mac, but it happens weird behavior on Windows server.

On Windows server, when I call `get_user_token` method, then it make me wait about 10 seconds and it returns 400 error with message "Current date\/time MUST be before the expiration date\/time listed in the 'exp' claim", however I try to call it again, works fine.

Server time is synchronized with NTP server.

Whant happen on Box? How can I fix this?

Ruby 2.3.1

Rails 5.0.0.1

Boxr 1.2.0

Should I ask at Boxr side?

PS C:\Users\foo\baz\foo\current> bundle exec rails console
Loading production environment (Rails 5.0.0.1)
irb(main):001:0>   def private_key
irb(main):002:1>     OpenSSL::PKey::RSA.new(Settings.box.private_key,
irb(main):003:2*                            Settings.box.private_key_pass_phrase)
irb(main):004:1>   end
=> :private_key
irb(main):005:0>
irb(main):006:0*   def user_token
irb(main):007:1>     Boxr.get_user_token(Settings.box.app_user_id.to_s,
irb(main):008:2*                         private_key: private_key,
irb(main):009:2*                         private_key_password: Settings.box.private_key_pass_phrase,
irb(main):010:2*                         public_key_id: Settings.box.public_key_id,
irb(main):011:2*                         client_id: Settings.box.client_id,
irb(main):012:2*                         client_secret: Settings.box.client_secret)
irb(main):013:1>   end
=> :user_token
irb(main):014:0> tok = user_token
Boxr::BoxrError: 400: {"error":"invalid_grant","error_description":"Current date\/time MUST be before the expiration date\/time listed in the 'exp' claim"}
        from C:/Users/foo/baz/foo/shared/vendor/bundle/ruby/2.3.0/gems/boxr-1.2.0/lib/boxr/auth.rb:90:in `auth_post'
        from C:/Users/foo/baz/foo/shared/vendor/bundle/ruby/2.3.0/gems/boxr-1.2.0/lib/boxr/auth.rb:24:in `get_tokens'
        from C:/Users/foo/baz/foo/shared/vendor/bundle/ruby/2.3.0/gems/boxr-1.2.0/lib/boxr/auth.rb:39:in `get_user_token'
        from (irb):7:in `user_token'
        from (irb):14
        from C:/Users/foo/baz/foo/shared/vendor/bundle/ruby/2.3.0/gems/railties-5.0.0.1/lib/rails/commands/console.rb:65:in `start'
        from C:/Users/foo/baz/foo/shared/vendor/bundle/ruby/2.3.0/gems/railties-5.0.0.1/lib/rails/commands/console_helper.rb:9:in `start'
        from C:/Users/foo/baz/foo/shared/vendor/bundle/ruby/2.3.0/gems/railties-5.0.0.1/lib/rails/commands/commands_tasks.rb:78:in `console'
        from C:/Users/foo/baz/foo/shared/vendor/bundle/ruby/2.3.0/gems/railties-5.0.0.1/lib/rails/commands/commands_tasks.rb:49:in `run_command
!'
        from C:/Users/foo/baz/foo/shared/vendor/bundle/ruby/2.3.0/gems/railties-5.0.0.1/lib/rails/commands.rb:18:in `'
        from bin/rails:9:in `require'
        from bin/rails:9:in `'
irb(main):015:0> tok = user_token
=> # token_type="bearer">

Thank you