Retirement tax questions

Thanks for responding. 

 

Yes. this is a solo 401k. You are correct, I will receive a 1099-R but it will be coded E as I understand since this is a failed conversion.  But my question is do I have to amend my tax 2021 based on Sec 301?

 

Just to clarify, this was from an after-tax account (not a Roth) into a Roth. As I understand, this is a failed conversion so I need to remove the excess within a 6 month period which I am initiating.