As explained on a previous post, your NAS can send you email notifications to alert or inform about changes: back up notifications, connection failure, etc.
If you have had email notifications configured in your NAS and they suddenly stopped, you are probably wondering what has caused it.
This happend to me and I only realized it when I stopped receiving emails when people commented on my blog post.
After reviewing the settings and verifying that they were ok, I suddenly realized that I had changed my password on my hotmail account and you need to change it in your notifications settings too:
Send a test email afterwards to confirm that everything is working again,