On the Gateway back side there is a sticker with the gateway UUID (Unique ID / Serial Number) identifying the gateway. Please keep this in mind, the serial number is used when adding the gateway to the user account and when accessing the gateway web user interface.
The sticker also contains the gateway MAC address, located below the QR code.
A copy of this sticker is provided in the gateway packaging. In addition to the UUID and MAC address, these stickers contain the gateway web interface passwords. Please keep these stickers, they may be used later.