But serious folks, Form 2553 can only be paper-filed.  The IRS was so behind that two new clients came to me saying the 1120S they tried to e-file for their new S corps were rejected because "We the IRS don't think yours is an S corp". 

After taking care of the two clients, I tried to e-file a client's new S corp (F2553 was filed in the first week of 2020), sure enough, it was rejected.  So, I had to do the same dog and pony filing.  (Basically paper-filing 1120S, pretending it was a late election under Rev Proc 2013-30, with an explanation that F2553 had been timely filed by certified mail dated Jan xx 2020.)

The 1120S was accepted and the determination letter was received by client in September 2021.

And we all lived happily thereafter.  

I don't know if the IRS is still behind in processing F2553.  Sharing this with you in case you don't know why it ain't 1120S while it should really be 1120S for a 2021 new S Corp client.