If you are getting an error by entering 0 (meaning you do not want to defer any self-employment tax), make sure you answered no on the TurboTax screen in which you are asked if you want more time to pay self-employment taxes.
Please follow these steps in TurboTax to check and/or change your election:
Hi there,
I followed your steps this is still triggering the Federal Review for max deferral line 20 for Sch SE-S to be auto populated with a 0. I hope this gets looked at as I am currently unable to complete my taxes.
If the above steps did not work, please remove the $0 that is in the box and leave it blank.