Why is the SIM card of the mobile phone changed to another mobile phone, and the text message is still sent in the mailbox? How to solve it?

The reason for this is that when you use the first mobile phone, its SMS storage is set to SIM card by default, and it will only be stored in the phone memory when the SMS of SIM card is full. If you want to delete a message, just delete it on any mobile phone. The solution to this situation is to find the settings in SMS or SMS settings that are similar. There should be a "storage location" in it, and you can choose "mobile phone" in it. If you can't find it, then the default storage location of this mobile phone may be a mobile phone or a SIM card. If it is a mobile phone by default, it will be directly stored in the mobile phone, and there will be no SMS on the SIM card. If the default SIM card is used, the SMS memory of the SIM card will only exist in the mobile phone when it is full. You can't see the default location, you can only identify it by changing your mobile phone and passing the SIM card.