TurboTax does not reject 6 digit IP PIN's. If you entered the IP PIN sent to you by the IRS for 2018 then the tax return should not be rejected by the IRS for the IP PIN. Maybe the 2017 AGI or your 5 digit self-selected E-file PIN would be rejected by the IRS, but not the IP PIN.
To enter a 6 digit IP PIN
- Click on Federal Taxes (Personal using Home and Business)
- Click on Other Tax Situations
- Scroll down to Other Return Info
- On Identity Protection PIN, click the start button
Or enter ip pin in the Search box located in the upper right of the program screen. Click on Jump to ip pin