VST stopped working in X1 but still works in 8.5

I must have done something but I am not aware of it. I use Sonar to sequence Hauptwerk organ software and the audio returns to Sonar "through" vst for processing by Reverberate.  This has been fine until I moved house. I know the midi information is getting to Hauptwerk but the audio is not returning. Diverting the audio to the asio driver instead of vst produces sounds.
If I load this configuration in 8.5, all works properly.  I must have done something BUT WHAT.  Help needed pleas.