I can not file due to Box15 not being filled out but it states clearly if blank leave blank. How do I bypass needing something in this box?

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