I received 13 notifications between 04:50 and 07:39 this morning, the oldest referring to a post from about 06:30 on the 8 Sept. Some from AMSIG and others from ATF.
I guess they may have been 'upgrading' the software and as quite usual in these cases failed to get it right and may be working through the backlog.
I did notice a couple of problems getting access to AMSIG over the last two days - this morning I could get the initial screen up but any attempts to select a topic led to a 'Server Fail' screen.
Notifications seem to have been working OK for me since then, though they do sometimes seem to be quite delayed.