Rejected for duplicate

[Angie47]

I made a Turbotax account for the first time, and input some information (profile and W2).
However, I was confused by a few questions, so I changed my mind to ask the CPA to file my tax return.
CPA filled out my tax return on his computer. (I don't know what his tax system is.)
When he submitted my tax return, it was rejected. He said the reason was that my tax return had already been approved by the IRS.
So I asked 'Turbotax Digital Assistant' to delete all my working forms so I could submit files from another system. But it was rejected again. CPA said that I need already approved forms to amend my tax return.  
But I can't find anything on Turbotax.
I remember Turbotax had automatically created some forms that I didn't make.
How can I find the accepted forms? How can I solve this problem?

[Mike9241]

Has the CPA considered that it's possible someone already filed using your SSN?  this would make it impossible to e-file.  you can give the CPA a power of attorney (form 2848) so he could contact the IRS on your behalf.

no amended return would be required.  your return would have to be mailed in and form 14039 would be included.

[Angie47]

Thank you for your kind answer.
The CPA considered that someone already filed using SSN. But this is my first time filing a tax return, and it's unlikely to use my SSN other than what I've been working on Turbotax.
In this case as well, can I give the CPA the power of attorney to do the work as you suggested?

[DMarkM1]

Yes, you will need to find out what was filed and when to help ascertain if a fraudulent filing occured and the steps to handle your specific situation once uncovered.