Thanks, Devlyn and Danielle, for your replies.
That is really an odd case. The last e-mail I got from Susan's was yesterday at 3:45pm CST, nothing further since then, including both of your posts under this thread. I checked again all my spam folders and spam settings, but they are all clear.
Interestingly, my subscription notifications still work in Tapatalk on my iPhone. According to Tapatalk I have missed at least 9 notification e-mails since yesterday afternoon.
I am not sure what else I can do on my end...
Heide