What do I do if my QPP box is empty?

Hello, this is my second time using studio tax for filing my tax return, and this time around, I've run into a problem. For one of my T4 slips, the QPP contributions (box 17) is empty. So I leave it empty in studio tax. But when I get to the equivalent box in my RL slips (that's for Quebec provincial) it says: "This box is linked to a federal T slip box. Please enter your T slips amount first and complete the remaining RL boxes". It won't let me set any of the boxes until this field is set in the the equivalent T4 slip. I tried putting 0.00, but that just defaults to blank (""). What should I do? Similarly, in another of my T4 slips, I have an employer that had QPP contributions, but no CPP. I will probably have the same problem there.