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Here's what it sounds like to me, when you create a user in exchange/active directory, they are defaulted an internal email address (typically of your domain, could be something like mike @domain.local
If that's the case, an external address needs to be assigned.
To do this, get on the server. Select Active Directory users and computers
. (start > all programs > administrative tools > )
Once inside, locate one of the users who can't receive outside email, they will likely be located either in Users, or Mybusiness > users, or Mybusiness > sbsusers. You'll have to expand the domain (double click it) if its not expanding in the AD users and computers.
Right click one of the users having problems and click Properties
. Click the Email Addresses
tab. This is where their email should be specified and set as their primary. If you don't see their external email listed there (which is likely the case), then you will need to click NEW
. Select Custom Address
, type out the FULL
, type out SMTP
Click ok. Now in the list for email addresses, highlight the one you just created, and click "Set as primary".
You can add as many email addresses as you like (their account will receive on whatever ones you add to it).
Try sending in a test address to the account you alter.
The only other possibility is if you have a spam filtering service where your mail goes before it is received by your company, such as Redcondor or something to that effect where you need to actually create the mailbox on the filter as well. But this is a pretty rare setup in general.
Let me know how it goes.