To activate or find your Kaspersky Small Office Security key, you should use the official activation code provided at the time of purchase. Note that unlike some other Kaspersky business products, Small Office Security cannot be activated using a standalone key file and must use the 20-character activation code. How to Find Your Activation Code
You are trying to activate the software with a key meant for a different Kaspersky product (e.g., trying to use a Kaspersky Standard key for Small Office Security).
The is not a USB drive or a physical dongle. It is a unique, digital alphanumeric code (e.g., AAAA1-BBBBB-CCCCC-DDDDD) that acts as your digital proof of purchase.
The is just a string of letters and numbers. But to a small business owner, it represents a safety net.