Recently during the vCSA 6.0 to 6.7 upgrade process, I encountered an error while deploying the new vCenter server appliance with an embedded PSC on the vCSA 6.7 installer.
The problem
In my case, I was trying to upgrade vCSA 6.0. If you notice that the network section is empty:

I cannot proceed, because of the error and it shows:
No networks on the host. Cannot proceed with the installation.
The Solution
The configuration on ESXi hosts and VCenter looked OK and obviously, it had port groups created in a standard virtual switch.
So the issue was that I didn’t have “VM Network” port group that is a default port group that is created once you deploy an ESXi host. In my case, it was auto-deployed with different port groups and that one didn’t exist.
Hence, as soon as I created a port group called “VM Network” in the host that I am trying to deploy the vCSA, it worked!

Now, I can see the port group and I was able to continue the installation with success!
I hope this worked for you as well.