On IRS Schedule K-1 (1065) or IRS Schedule K-1 (1120S). After answering the questions and inputing Box 20 Code Z it ignores my entries and tells me I cannot efile.

It's possible you missed step 3 of the instructions below.

When entering your K-1, check that it has Box 20 Code Z. You don't need to enter any amount for Code Z. 

1. Continue with the interview until you see "We see you have Section 199A information."
2. Check the box that applies (usually the first option).
3. On the page "We need some information about your 199A income," be sure to check the first box and enter at least one type of income.
4. Check any other boxes that appear on Statement A and enter the related amount.
5. Continue back to the K-1 summary page.