I'm a non filers so what else can I do
If you used the IRS non-filers website for the stimulus payment then you filed a 2019 federal tax return. The non-filers website is only if you had no requirement to file a 2019 tax return.
Now that you are filing a 2019 tax return the IRS is rejecting your e-filed return since the IRS has already received a 2019 return with your name and Social Security number.
See this TurboTax support FAQ for how to proceed in filing the 2019 federal tax return - https://ttlc.intuit.com/community/tax-topics/help/stimulus-how-to-file-your-return-after-getting-rej...