To add to what I edited in my previous post, the draft of the response to support was saved in my saved-drafts folder, but wasn't editable when I opened it. I needed to drag it to the Drafts folder where it could be opened for editing. (Confusing.)
And I still couldn't send it. I needed to open OWM (the smtp server that GO uses for sending, according to my GO account settings) in order to successfully send it.
Ah, well. Happy Friday the 13th.