I live in tn, worked in tn but on w2 the employers address in VA. When filing it will not let me put TN in for the state for box 15, help

Several  states do not have a state income tax.  So these states will not show up in certain drop down lists.   Leave boxes 15, 16, and 17 blank when you enter a W-2 for these states.

Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington and Wyoming