I cannot register my new device because "This device already registered to another account."

Zyxel_Melen

Although the device has been removed from the organization, the previous user still owns it.

Please download the Nebula Mobile APP [Android] / [iOS] and scan the QR code sticker on the device to register.

Here are the guides for each product line:

Access Point

Switch

Firewall (ATP/USG FLEX)