Exception rules are not working when endpoint clients use Lotus Notes
In Lotus notes if you add someone to your local address book, you can make a short name for them.
for example C Allpost
If they try and send the email using the short name the exception will not match and the email will be blocked.
When the end user hits F9 it will change the email address into a fully qualified email format. This will allow the exception to match and the email will not be blocked.
Add a message to the blocking response rule stating that F9 must be pressed prior to sending email to ensure the correct format is used.