12306 why is the trip reminder message sent to the secondary card?

12306 The trip reminder message was sent to the secondary card probably because you filled in the number of the secondary card when you purchased the ticket. In this way, the 12306 system will send you specific travel information through the secondary card number, so that you can keep abreast of travel arrangements and make corresponding adjustments. At the same time, it is recommended that you check your ticket purchase information when you receive this kind of information, so as to prevent the deviation from causing the adjustment of your travel plan. In addition, pay attention to protect your identity information and avoid disclosure.