Q. What is a QR code? QR code is a registered trademark of DENSO WAVE INCORPORATED.It is a square frame printed with black and white squares, which can be scanned using the camera function. Related articles Q. What is Address book? How do you use it? Q. Error (such as “It is busy at the moment.”) is displayed and I cannot use the service Q. The notification “Update to the information requested in e-Tenkyo?” was displayed. What does it mean? Q. I cannot complete my initial registration. An error message such as “Contains invalid characters” or “Incorrect format” is displayed when I enter the email address for registration Q. How do I change the login e-mail address?