BxAdmin - Session not found, please log in again

How to solve "Session not found, please log in again." errors, or a random "Unable to login: Unauthorized" error.

Problem

If you receive the error message: "Unable to login. Unauthorized" in BxWebManager, and also receive error message  "Session not found, please log in again." in BxAdmin, it may indicate that the BxEngine service is running on different servers/VMs with the same license. If you refresh BxAdmin and happen to catch the correct session at the right time, you might also see an error in the log: "Server is not licensed. License registered on a conflicting server".

This error can occur if you clone a VM without deactivating the BxEngine/BxSmartPrintPro services on the original server, or if an old server has been restarted without having deactivated the services beforehand.

Solution

Stop and deactivate the BxEngine (and BxSmartPrintPro if it exists) service on the old server/VM. Wait a minute and then refresh BxAdmin. 
You may encounter the Setup wizard when you refresh. You can close this, open Installation, and then select the correct ERP system → Save → refresh BxAdmin.

Be aware of the UUID/BIOS serial number when moving or cloning a VM, as this should remain the same. If not, the license must be released by us so that it can be revalidated.