capistrano3 permission denied (using proxy)

Question

I'm trying to migrate my capistrano v2 script to the new v3.4 version.

All went well with development stage: I have one EC2 instance, and the deploy completed without errors.

I'm having some troubles with my production script, because I've got a proxy (EC2 instance) before my production servers (EC2 instances too); in my capistrano v2 script all was working, now I'm using cap-ec2 + capistrano v3.4 to deploy my application only to tagged servers, but when I try it I get "Permission Denied", my production servers refuse my key.

Maybe I've set something wrong with proxy parameters in my script, can you please help me?

Thanks a lot!!

Here you can find proxy parameters:

CAPISTRANO V2 (working)

set :gateway, "[email protected]"
set :ssh_options, { :forward_agent => true }
default_run_options[:pty] = true
ssh_options[:port] = "22"
ssh_options[:keys] = [File.join(ENV["HOME"], ".ssh", "id_rsa_deploy_myapp")]

CAPISTRANO V3 (not working)

require 'net/ssh/proxy/command'

set :ssh_options, {
  user: "deploy",
  keys: %w("~/.ssh/id_rsa_deploy_myapp"),
  auth_methods: %w(publickey),
  forward_agent: true,
  port: 22,
  proxy: Net::SSH::Proxy::Command.new('ssh xxx.xxx.xxx.xxx -W %h:%p')
}