My Passport Ultra Will Not Backup Another Passport Ultra

WD External Drives WD Portable Drives
1

Both passports show up in DW backup. I selected one as backup to and then selected the other one to backup from. Is there something I am missing?

2

Hello,

Please refer to the following KBA article:

https://support-en.wd.com/app/answers/detail/a_id/12279/