Typically, leaving the not applicable section blank is preferred. However, in this case, your reply is required.
You have two other options to try.
Option 1: Enter 0, reflecting the amount you wish to use in calculating a deferral.
Option 2: Try entering 280/365 of your income for 2020 in this line.
[Edited 02/10/2021 | 10:35 AM PST]
@rclerkin
