I have the same problem. Did you solved yours?
Basic alerts seems to work normally but when I try to create an advanced alert with email, that doesn't work. When I click test alert, I receive email normally. But in NPM alerts tab I can't see those alerts and I don't receive any email when I try to test it.
My plan is to create alert for group nodes. If one node in group goes offline/warning state --> send email (any day, any time).
I don't know what to do.. I have checked alert times, regedit etc.. but doesn't work.
Does anyone have this working at the moment?