Are you trying to transfer the previous year online return into Pro-Series? It can't be for the same year. Like 2020 into a new 2021 return. What error message do you get?
Did you see this article? How to Transfer Turbo Tax to ProSeries
https://proconnect.intuit.com/community/convert-data-files/help/how-to-transfer-turbotax-returns-to-...
