2021 tax return filled, now IRS says I owe

I filed a 2021 return.  I have a summary PDF copy.  IRS says I owe.  I lost the electronic file I filed.  What should I do next?  Recreate the 2021 as a new file?  If that shows a mistake or not, then what are my options to replace the previously filed return?  I have no electronic file to amend.