Non-filers TurboTax Stimulus Registration preventing someone else from claiming my dependent

I filed with TurboTax Stimulus Registration, as a non-filer, and still didn't get the money for my own dependent for the stimulus. I didn't make any money in 2019, and just did the turbotax registration for the stimulus money. I let my dad claim my dependent for 2018 and was going to let him claim her for 2019. When I submit his return it is getting rejected because it says someone else is using her social security number on a 2019 return (which I am assuming was me when I registered for the stimulus with TurboTax). I didn't use her as a dependent for a child tax credit or deduction for 2019 so why can't my dad claim her on his return?