Mercedes has remotely deactivated unauthorized Startkeys via online checks in Xentry 07/2022 and later. If your Xentry has an active internet connection, it can phone home and blacklist your key.
If you are an authorized Mercedes-Benz dealer or certified body shop, the process is standardized: startkey xentry
A is essentially the licensing file required to activate the Xentry software. Without a valid StartKey, the Xentry software is essentially a shell. It may open, but it will not communicate with a vehicle, or it will restrict access to vital functions. startkey xentry