I am trying to file with my military W-2 form, when I try to file it the app says this is not a valid military W-2, which is wrong. Does anyone know how to fix the app?

I assume you may have snapped a picture of your W2 to transfer to your tax return in the App.  My suggestion is to exit the App and open a browser.  Sign in to your TurboTax account there.  Go to the "W2 topic" in "Wages and Income."  Delete/re-enter the W2 information and be sure to delete/backspace completely before re-entering the information to be sure no stray spaces/characters were transferred.  

Complete the topic interview and then try to re-file in the browser.  

Annnd...on a page just after the main W-2 that shows all the boxes and amounts.

There is a page with a whole Loooong list of checkboxes.

You have to check the box that indicates that the W-2 is for Active Duty Military.

....Civilians may get DFAS W2 forms too.  You have to tell the software, thru the checkbox, that is it for Military service.