My 1099-R is missing box 16 because it's not applicable but Turbo Tax insists I have to have it as it can't be greater or equal to gross distro or state distro. Why?

Wife cashed out her 403B. The 1099-R she got does not have a Box 16. on the back it states box 16 isn't there because it isn't applicable but Turbo Tax says said box can't be greater than or equal to gross distribution or state distribution.