The license file (extendsim.lic) relies on the identity of the Server. If the Server's MAC/Ethernet address changes, its identity changes, the license file fails, and the License Manager stops working. These changes can happen if the Ethernet card or WiFi card is changed, or if the Server is a virtual machine that uses dynamic MAC addresses.
Some hardware virtualization products, such as Microsoft's Hyper-V, create virtual machines (VMs) that, by default, have dynamic Mac/Ethernet addresses. For the License Manager to work properly on a virtual Server, the Server must use a static MAC/Ethernet address. If the Server uses dynamic MAC/Ethernet addresses, you must change the settings in the VM's Manager so that the Server uses a static MAC/Ethernet address.
You might not see an issue unless the Server restarts and chooses a different MAC/Ethernet address. If you've experienced this failure, change the Server to use a static MAC/Ethernet address. Then contact our Sales department so you can reactivate and get a new license file.