On my 1099-R form Box 7's distribution code says S. It's not letting me move on because it says "The IRA/SEP/SIMPLE box should be checked on your form" But it's not.

It's wanting me to check the box in order to move on OR to change the code to a different letter. But the form does NOT have the box checked and it DOES read S for the code. I don't want to incorrectly select something but it's NOT letting me move forward without making one of the changes.