JSAPI Token for REST API Oauth Token -> token_rejected error

gistfile1.rb

get '/ajax/linkedin_auth' do
  cookie = JSON.parse(request.cookies["linkedin_oauth_#{API_KEY}"])
  verify_linkedin_cookie(cookie)
  consumer = OAuth::Consumer.new(
    API_KEY,
    SECRET_KEY,
    {
      :site => "https://api.linkedin.com",
      :http_method => :post,
      :request_token_path => "/uas/oauth/requestToken",
      :access_token_path => "/uas/oauth/accessToken",
      :authorize_path => "/uas/oauth/authorize",
    }
  )
  begin
    request_token = consumer.get_request_token
    access_token = request_token.get_access_token({}, {:xoauth_oauth2_access_token => cookie[:access_token]})
  rescue => e
    log.info(e)
    binding.debug!
  end
  binding.debug!
end

def verify_linkedin_cookie(cookie)
  base = cookie["signature_order"].map { |field| cookie[field] }.join
  key = SECRET_KEY
  signature = Base64.encode64(OpenSSL::HMAC.digest('sha1', key, base)).chomp
  assert(signature == cookie["signature"], "The cookie we received from LinkedIn has an invalid signature - it may have been spoofed, or our LinkedIn secret key may have changed. The cookie in question: #{cookie}")
end

The error occurs in line 17 and is an instance of #<OAuth::Problem: token_rejected>