When I enter IRA contributions for 2020, TurboTax tells me that I only get a deduction if I contributed before 2021, and say I do not get a deduction if I contribute in January through April 15th. i h

[Miss MCJ2]

To me that sounds like the program is not giving the correct information.  Call the helpdesk and ask them to file an investigation..  Ask them to contact you with results of that investigation.  If the person who answers does not understand, request to speak to their manager.

[Critter-3]

Much of the 2020 program is still under construction and working off 2019 information ... once that section is updated it will work correctly.  

[dmertz]

You are misinterpreting the result.  Apparently your traditional IRA contribution is nondeductible and you also made a IRA distribution or Roth conversion in 2020.  Generally, nondeductible contributions made for 2020 after December 31, 2020 are not treated as part of your basis in nondeductible traditional IRA contributions that reduce the taxable amount of your traditional IRA distribution or Roth conversion but simply increase your basis in nondeductible traditional IRA contributions that will apply to distributions or Roth conversions in 2021 and beyond.