Ive got a couple of users who can receive but not send any email.
Everyone else works fine.
The BlackBerry Manager shows no problems.
Ive tried reactivating the devices, but no joy.
Please make sure that the users are members of the BESadmin group and confirm that they are also inheriting permissions to 'Send As'.
Please see the two links below regarding a revoke of the 'Send As' permissions as a result of an MS patch. First link to the BlackBerry KB, second to the Microsoft KB.