sandisk extreme 55ae scsi disk device disconnected issue

My new disk is disconnected often when I copy file into the disk, make me backup the photo from my iPhone fails only can copy one by one folder

How do I troubleshoot?

Hi @CharlesK,

Have you opened a Support Case? If not opened, for more information, please contact the SD Technical Support team for the best assistance and troubleshooting:
https://kb.sandisk.com/app/ask