Geoffrey,
Thanks. I'm trying to get my host to help me set things up so that the domain always automatically forwards to
https://theresamatherfantasyshop.com/dir/ instead of to the unsecure
http://theresamatherfantasyshop.com . I think that would move users past whatever the browser problem is.
I don't use Firefox all that much either any more. I wouldn't even have known about the problem if someone trying to buy something hadn't contacted me.
FWIW, it all seems to have started with changes to security protocol in AbanteCart 1.2.11. I'd used .9 and .10 without problems, and without an SSL certificate. Once I did the .11 update, it all became a real mess. I have made a note to be very certain to make a full backup before doing any update at all in the future!