Sumif formula not working

[zackvillani]

This is the formula i am using in my excel =SUMIF(Sales!,Scenario_1,TableSales[Quarter_1]) which my professor told us to use. and when i press enter it says "there is a problem with this formula,... excel thinks this is a formula." It is a formula and excel won't compute it. I need help!!!

[#2]

@zackvillani First try without the exclamation mark after Sales as that would be an invalid range name. 

If that doesn't fix it, can you share the file?