Updated to 4.0.6 on Synology - reset config.ini
I updated VirtualHere to 4.0.6 from 4.0.5.
It created a default config.ini, which in addition to losing the license info lost any other configuration changes there.
I don't remember all of the changes I might have made over time because it's never happened before. Maybe you could make a backup of the current config file, certificate etc before the install/upgrade?