Is the box greyed out or are you trying to click it and the check will not appear in the box?
You may need to clear your cache and cookies. Make sure your return is saved in your TurboTax account and then sign out. Clear the cache and delete the cookies on your computer, open a new browser, sign back into your account and try entering your information again. You may also want to change browsers, for example, if you are using Chrome, try switching to Firefox.