The following assumes you have signed up to receive VAC Alerts, if not you need to sign up.

Several organizations are using software to block spam, unfortunately the following email extensions may consider email from VAC as spam (VAC alerts being one example) and you may not receive the email or it may be random whether you receive it or not.  If you are on the list you might want to change to another email like @yahoo.com etc., to be sure you receive alerts etc. 

The list below have at times, blocked VAC email as spam.

@cablevision
@sharpsec.com
@courts.state.ny.us
@vcmail.ouboces.org
@vcsd.ouboces.org
@catskill.com
@anthem.com
@mobile.mycingular.com
@hvc.rr.com

This software blocks the email before it gets to your inbox.  However, that said you should check any spam folders you may have.  If it is in your spam folder you should be able to mark it as not spam. If not then it is being blocked by the server that you get your email from.