Me too...  Forum notifications are not working.  I have not yet checked Blogs, but Forums are definitely NOT working.  However, all settings are in place, and Host Settings are in place.  Also, I receive all Portal-level notification e-mails.

Do you have access to the server to reboot it?  I had the same problem and after rebooting the server everthing worked fine.  I'm not certain, but I think it may have had to do with my virus scanning software hanging.

Thanks,

Don

If your hosting provider has a trouble ticket system, you may want to create a trouble ticket describing the fact that email was working but now it's not.  Assuming you haven't made any changes on your end, this would appear to be due to either a configuration change on their end or due to a process that needs to be restarted.  if either of these is the case, I think they would interested to know since other customers will be experiencing the same problem.  Please let us know if this doesn't address your issue.