Announcement reposted from Amazon Japan:
Notification feature on the LINE app will help to make sure that you don’t miss critical information from Amazon. The app will send an alert when your seller account is at risk of deactivation due to a failure to achieve performance indicators or from policy violations. The message will include the actions necessary to continue selling.
What is the LINE official account?
The sell on Amazon LINE official account sends notices via email and Seller Central on required actions related to your account status, listing status, and payment disbursement errors.
Note: Depending on the cause of the deactivation of product listings, there is a possibility that notifications will not be sent on LINE. In addition, due to the related system, there is a possibility that you may not actually start receiving LINE notifications until later than the date when notifications are available. Therefore, please be sure to check your email and Seller Central.
Go to the LINE Official Account to connect your account.
Download this PDF document for instructions on how to receive and use LINE notifications.