2020 Federal amended return rejected after efile

Got this in the email - 

/Return/ReturnHeader/FilingSecurityInformation/TotalPreparationSubmissionTs - Data in the return is missing or invalid. Please double check your entries. 

 

Had efiled using turbotax online - but it now directs me to download .tax and open using desktop software. When I open - it doesnt provide option about a rejected amendment - only if I want to file/review. I just do that anyway - and getting stuck at the page where it insists Signature date must be in 2021. (Though You can efile amendments beginning 2020).