My 2020 amended tax return, generated through TurboTax and filed manually was rejected by the IRS. Pretty sure my amendment was properly prepared. What do I do now?

The original return I filed had an error. So I filed an amendment. It was rejected when I efiled. So I printed and manually filed the amendment. After a year, IRS rejected it. My amended return papers were properly prepared. I hear IRS was backlogged last year and their systems were acting funky. What do I do now?