If you are unable to receive your authentication code via SMS, please check for the following potential problems:

• Bad Mobile Network Connection
  SMS messages are sent using the connection supplied by your mobile network operator.
  Hence, if you are in a location with bad connectivity or if your device is set to Airplane Mode,
  SMS messages may be delayed or not received at all.
  Check your connection settings and try once again in a location with better connectivity.
  
  
• No SMS Support on Phone Contract
  Some phone contracts do not support SMS, or SMS may be available only by signing up to additional options.
  Please check the details of your phone contract.
  
  
• Settings that Prevent Receipt of SMS Messages
  If your device or contract is set to prevent receipt of SMS messages or if they are set to only receive messages from specific registered users,
  you will not be able to receive your authentication code.
  The method for changing these settings will depend on your mobile device and mobile company,
  so please refer to your mobile device’s user manual or contact your mobile network operator.
  
  
• Exceeded SMS Message Storage
  If you have exceeded your SMS storage capacity, you will be unable to receive any new SMS messages.
  Please delete any unnecessary data and try issuing an authentication code once again.