Async task failing on ruby worker. I want to send directly

Hi I have used async task to send emails and sms from my ruby server in the past.

This is not working

 def notify_customer_create
SendEmailWorker.perform_async('EstimationMailer', 'new_estimation', self.id)

 end

This is working

def notify_customer_create
  EstimationMailer.new_estimation(self.id).deliver

 end

So i got around it. But now i am facing problem to send sms the same way.

Here is the code i have:

def send_on_create_confirmation_instructions
 unless self.guest
  phone_number = self.mobile_phone.number
  self.update_attribute(:confirmation_sent_at, Time.now)
  SendSecretCodeWorker.perform_async(phone_number, self.confirmation_token)
end
 end

Here is the definition:

 class SendSecretCodeWorker
  include Sidekiq::Worker
  sidekiq_options retry: false
  def perform(number, code)
MobileOperator.send_code(number, code)
  end
end

Somehow perform_async doesnt work. How to send it without using "async" as i did for emails?