If Adext AI detects that any of the ads in the ad group(s) you select does not support desktop delivery (mobile-only ads) then Adext AI will not be able to clone that ad and set budgets for audiences on desktop computers.
What to do:
Adext AI will automatically deselect the Desktop demographic for you, so if desktop doesn't matter to your experiment then go ahead and continue the process
If you want Adext AI to include Desktop delivery in your experiment then you'll need to either change the ads in your ad account so that they support Desktop, or select another ad group for the experiment
If you have any questions on this, feel free to message us by clicking the little chat icon in the bottom-right of your screen.