V7 audio in from line i/p axia

Hi, I have for some used successfuly an audio in from PC and configured a cartwall button as an enable audio feed to air.
I use this as a remote mic for home users.

Recenty I added a differrent audio feed. Lets say PC audio IN 6. Whilst I see audio ok at the pc level Im unable to get it to pass into mairlst.

Any ideas here as it has worked before for me.

FYI this is studio version. I have it occuring on 2 PC’s.