As I understand it, you have no choice but to print, sign and mail the return at this point.

https://ttlc.intuit.com/discussions/lounge/4618410-kyi-form-2210-part-ii-box-a-e-file-reject

Alrighty then, that is what I will do. Thanks Carl!

...and now another related problem: I can view the Penalty Explanation form but TT will not allow me to print, nor can I find such a form on the IRS website.  Can I simply write my comments on a generic form (i.e. plain sheet of paper) and include it with the 2210 for mailing?  One other thing... I don't believe that I really need to file the 2210 at all, since there is no underpayment.  In fact, there was a major over payment.  Payment for the year exceeded liability and quarterly estimated payments each exceeded 1/4 of liability. What do you think?

Update:  I found a work-around under "similar questions" and was able to override the checked box which made the 2210 disappear.  Refile was accepted be the IRS. Woo-hoo!