nanoframework esp32 wifi connection fails

I am trying to connect to wifi using esp32 nanoframework. Have tried various samples, for example: https://github.com/nanoframework/Samples/blob/main/samples/Wifi/ScanWiFi/Program.cs

I am getting the below exception on this line:

WifiAdapter wifi = WifiAdapter.FindAllAdapters()[0];

Exception:

Starting Wifi scan
    ++++ Exception System.InvalidOperationException - CLR_E_INVALID_OPERATION (1) ++++
    ++++ Message: 
    ++++ System.Device.Wifi.WifiAdapter::NativeScanAsync [IP: 0000] ++++
    ++++ System.Device.Wifi.WifiAdapter::ScanAsync [IP: 000d] ++++
Exception thrown: 'System.InvalidOperationException' in System.Device.Wifi.dll
message:Exception was thrown: System.InvalidOperationException
stack:System.Device.Wifi.WifiAdapter::NativeScanAsync
System.Device.Wifi.WifiAdapter::ScanAsync

I have tried various things such as

• reboot device
• manually enter network config, set enabled etc.
• reflash

So looks like it was an issue to do with the same SSID on 5GHz as I had on 2.4GHz.

Things I looked at that weren't actually necessary to get it working

• special config for the router. What I had by default for GW, DHCP, NTP etc. was all fine.
• special network config in VS for the device. The "automatic" settings actually all work and the code samples work well too. e.g. : https://github.com/nanoframework/Samples/tree/main/samples/SSL/SecureClient_WiFi

The only thing was that the esp should connect to the SSID on 2.4GHz and not the same one on 5GHz.