Got a letter from the IRS that they did not receive my 2019 tax return. Can I e-file again?

It's December 2021, and I recently received a letter from the IRS that they did not receive my 2019 tax return.

1. I e-filed on time through TurboTax.

2. It was apparently accepted, according to my TurboTax account.

2. There is a credit in my IRS account for the taxes I paid at the time of filing.

 

They want a newly signed return, but is there a way to e-file again?