I am near certain you will need a EFIN as a user of Proconnect .................

I have to ask, did you just wake up one morning at the end of February and decide you were going to prepare taxes ?    

You need an EFIN to efile returns.

Not needed for paper filing.

As long as you don't prepare 10 or more (or is it more than 10??) you aren't required to e-file.   To e-file, an EFIN 'is' required.  Given the current state of affairs, you might want to start on that so you are ready for next year 😉

There is a 'waiver/form' that is supposed to go with the returns, stating the *why* for not e-filing.  

@abctax55 You are promoting the Big Lie by saying "prepare 10 or more returns."  I prepare hundreds of returns and I don't have an EFIN, because I consider the IRS rules for obtaining one to be unethical for my profession.  I don't file any returns -- literally, take them to the mailbox for a client -- which is what the rule requires.  

In your settings under ProConnect software there is a section for EFin authorization and I do not believe you can electronically file any returns without this authorization. You can use the software and paper file only without an EFin. I believe the software is in compliance with the IRS rules requiring a tax preparer to have an EFin in order to electronically file. Refer to the IRS website.  https://www.irs.gov/e-file-providers/faqs-about-electronic-filing-identification-numbers-efin.