Configure old project to recognise new d/a interface

I have opened an old project made with Cubase 6, when I used an Audio-Quattro digital/audio interface. I now use Cubase 10 and a Focusrite interface. The recording will play back to my speakers via the Focusrite, but when I export a mix ‘internally’ to the project folder the result is silent, as is an attempt to burn it to disc. What do I need to do to have it export a file that the system recognises?(Apologies if there is very basic ignorance behind this question).

You have to check your routing. Look in the export window and see what you’re using as a source for your export. Then go through your signal flow and make sure that that source actually has the mix in it.

If you want others to look at it then you’d probably have to post some screenshots of the export window and the mixer.