Get your taxes done using TurboTax

Box 14 of your W-2 is for informational purposes only. Meaning it doesn't have any effect on your tax return.  Make sure that you have filled out all 3 sections provided for Box-14. Make sure you select a category type. See the image below for reference

This image is just to serve as an example. 

If you still get an error message after entering all the information, try leaving the box-14 section empty altogether, as it won't have any effect on your return.