Missing Password

I have a My Book 8TB, and I never used a password.
Now when I reboot my Mac (big sour) the disk don’t appear, and get a system msg:

“WD Ddicovery Helper wants to use your confidential information store in “7SGYTGMC” in you keychain”

My keychain don’t have “7SGYTGMC”, and I never use a password.
I have checked this support and used the program “WD Security”, and it show my disk with a locker.

Any Help ??
Thanks