It depends - Are you looking at a NQ chart, or a MNQ chart?
If you are looking at a NQ chart and wish to have the "Primary account" trade MNQ you need to have cross trade enabled on that chart that the DOM is attached to. If you then check "Cross trade" under the trade copier account settings, all of these accounts will be trading MNQ.
If you just want to trade NQ across the board make sure cross trade is
not checked anywhere.
Regarding the copier not working - Did you have the account you created from the trade copier selected in the drop down list on the DOM?
For example if the trade copier account that you created was called "Copy Account" - You need to have "Copy Account" selected in that drop down list in the DOM for the copier to work correctly.
Hopefully that makes sense