AlphaElwedritsch I've had this problem several times where the installer would get stuck in a loop and wouldn't proceed because the drive was partitioned.
I've had that too it means you didn't quite format the drive to the installer's liking. until, like you, I learned how to make gparted do my dirty work.
theking2 The network is quite open as I can write you this message :-) So Solus installer must check for a specific server or domain it's not telling about.
ahhh...before reading @Harvey I just assumed you had a cord plugged into a wall like I did. Wifi has its own built-in variables.
Still:
theking2 Or in other words: what causes Solus installer detect erroneously that it is not connected to the internet?
my gut (unscientific) is telling me some unholy union between the vm and the network manager. Your own LAN firewall can most certainly be the cause.
You haven't eliminated any variables yet. Try it bare metal. You can always abort insall. If that installs you've already started the elimination.
I'm also semi-retracting my "solus is looking for geo-location" during install which I do not factually know. I can remember in some distros the default would be NYC or Helsinki (I live western usa) and I just went ahead with install without changing 'detected city' (if that's what it actually did), successfully. I'm semi-retracting because I don't if where you live is a requirement of solus' installer. in others its disabled.
edit:
theking2 what causes Solus installer detect erroneously that it is not connected
my guess is something is telling the installer it's not connected, despite the obviously open connection. what could that be? it seems like it would be such a simple thing to establish the old handshake, if you will.
maybe @AlphaElwedritsch is right and it's the media or partition--it's as longshot as any of my guesses 😉