2. Select the "System" option from the drop-down box in the setting interface;
3. Next, select the "Backup and Recovery" option in the system interface;
4. Select the "cloud backup" option in the backup and recovery interface;
5. Next, select the backup date before the SMS icon disappears in the cloud backup interface;
6. Next, select the "Restore" option in the lower right corner of the backup details interface;
7. Next, select the "Restore" option in the pop-up box, so that the disappeared SMS icon can be retrieved;