Lost my encryption key after reboot server

Hello,

Sorry for my epic english :(

I have a strange issue.

I have generated an encryption key with the tool (UI.Portal.EncryptionCreate.zen).

Then  I activate my key for data encryption (UI.Portal.EncryptionManaged) and encryption work fine.

But when I reboot my server the key is removed from the data encryption key list (UI.Portal.EncryptionManaged) and I have to re-activate the key.

Perhaps somebody have an idee ?

Cache version : Cache for Windows (x86-64) 2016.2.2 (Build 853U)

Windows: Windows Server 2012 R2 Standard

Thanks

Sébastien