This usually happens due to deleting a device or network database without first de-commissioning the devices in the database.
Solution: De-commission devices before deleting any devices or network databases.
In some cases some case third-party Apps synchronize their Apps databases with the LNS server resulting in lost LNS credits due to bugs in the third party tool.
You can also lose credits if you decommission more devices than the computer’s current LNS license supports. The LNS license defines how many credits have been purchased for this computer. If you try and decommission more devices than have been purchased for the computer you will lose those extra credits. This problem usually occurs if you commission devices on one computer and then move the network database to another computer.
Solution: Determine how many device credits can be restored to the LonMaker or LNS license before decommissioning many devices. If you need to decommission more devices then the license supports then decommission a subset of the devices, and commission those or new devices instead of doing it all at one time.
To determine how many devices can be decommissioned check the LNS license status using checklic or the LNS License Utility (see section 6 for more details).
LNS: Run checklic nsseng.exe
“Num purchased” - num_used = (Num_allowed – 500) – num_used
(564 – 500) – 10 = 64 – 10 = 54 unused_credits
If the value of unused_credits is a positive number then you can de-commission up to num_used amount (in the example, num_unused is 10). If you de-commission more than 10 credits then you will lose credits (e.g., if you de-commission 15 devices then you will lose 5 credits).
If the value of unused_credits is a negative number, then you are in deficit credit mode and you need to de-commission enough devices to get out deficit credit mode or purchase enough credits to get out of deficit credits. If you de-commission more devices than required to get out of deficit mode by a single credit, getting a num_used of 0 or 1 will cause you to lose credits. For example, if unused_credits = -12 and de-commission 16 credits, the 1st 12 de-commission device are used to get the license out of deficit credit mode and the last 4 credits are lost.