Transfer 2021 Turbotax 1040 to Proseries 2021- Error

[usmcretd]

I am trying to import (transfer) a 2021 Turbotax Online 1040 file to Proseries 2021.  The client downloaded the file from Turbotax online with a .tax2021 extension.  I followed the instructions to transfer it to Proseries, but when I click on transfer I get an "Unknown error (120)" error.  This is a big return with lots of W-2s, 1099-Rs, K-1s, etc. and I don't want to type it all in again to Proseries.  Does anyone know a solution?

[Just-Lisa-Now-]

Do you have the TT Desktop file or the TT Online file? I think it only works with a file from the Desktop version.