If you're not transferring your LINE account with an easy transfer QR code (e.g. the QR code login option) or with the same phone number registered to your account, you will need to turn on the Skip 2-step authentication setting. To do so, go to Settings > Account transfer options in the LINE app.
You need to turn on the Skip 2-step authentication setting when:
• Logging in to your LINE account after changing to a phone number that is different from your registered phone number. (Only for users in Hong Kong, Japan, Korea, Taiwan, and Thailand.)
Note: This also includes when restoring from an iTunes or iCloud backup using your Apple ID.
Useful info- Be sure to transfer your LINE account within 36 hours of turning on the Skip 2-step authentication setting. If 36 hours have elapsed, turn this setting on again to reset the timer to 36 hours.