I keep getting this same error as well. However in my case my side business operated at a loss this year so my business income is negative. Obviously I can't defer anything as there's no income to defer. (I do have income from a W2, but this side hustle was at a loss). It won't let me type 0 in this box.
How can I fix this? (I'm using TurboTax Home & Business)
Sch SE-T
Line 2 = -3,342.
Line 3 = -3,342.
Line 4C = -3,342.
Line 14 = 5640.
Line 18 = 0. (Max deferral is too Large)
