Best thing to do it call in tomorrow for tech support while at the machine and someone can walk you through everything. Let them no the model and it works in DC, not in AC mode on aluminum.

Check list for more testing before the call.

2T, AC mode, TIG mode selected, turn off pulse and all green knobs but maybe some post flow. torch in the minus, clamp on good and close the welding area. Sure you have already done it, but worth re-checking.