Ruby AdWords API returning AuthenticationError.OAUTH_TOKEN_HEADER_INVALID

Have someone worked with Google AdWords API ?

I’m using

  • devise
  • omniauth
  • omniauth-google-oauth2
  • google-adwords-api

I’m getting the token from oauth callback:

class OmniauthCallbacksController < Devise::OmniauthCallbacksController
def google_oauth2
session[:token] = request.env[“omniauth.auth”].credentials

endend

and following the example of adwords on rails
https://github.com/googleads/google-api-ads-ruby/tree/master/adwords_api/examples/adwords_on_rails
to
get api instance:

def adwords_api
@api ||= create_adwords_api
end

def create_adwords_api
api = AdwordsApi::Api.new Rails.application.config_for(:adwords)

token = session[:token]
if token
credentials = api.credential_handler
credentials.set_credential :oauth2_token, token
credentials.set_credential :client_customer_id, current_user.id
end
api
end

but when I try to get campaigns, It returns an error:
[AuthenticationError.OAUTH_TOKEN_HEADER_INVALID
@ ; trigger:’’

and based on the log, this is the url of request:
[2015-01-09T10:12:44.237172 #6481] DEBUG – : SOAP request:
https://adwords.google.com/api/adwords/cm/v201409/CampaignService

How can I fix this?