1099-R Excess contribution by employer

Hi.  I stopped working in 2020, but my employer made a contribution to my 401K account in early 2021.  Then, a few months ago I received a letter from Fidelity, saying that my employer had made an excess contribution and that in order to avoid a 6% penalty, I needed to withdraw the amount from my 401K.  I received a 1099-R, with amounts in Box 1, Box 2a, Box 5 and Box 7 (distribution code "E").

 

The problem is that I don't know which of the 3 different amounts (Box 1, 2a or 5) I'm supposed to withdraw from my 401K.  I called Fidelity and they couldn't answer the question.

 

I haven't had any success reaching the IRS (not surprisingly), so I thought I'd try this forum.  

 

Thanks!