Hello,
Which EV version?
In general, this message indicates the mailboxes are not enabled for archiving.
To check:
In the EV COnsole, click on the sitename.
In the right pane, select Mailbox Management
Select Enable Mailbox
Select an Exchange server
Select all available mailboxes
if this returns a list of mailboxes, the message is correct. Select all mailboxes, select enable.
To verify the way you set up EV, check your provisioning groups. On each group, tab Archiving Defaults. Verify a tick is set in 'automatically enable mailboxes'.
If the above is set, and the above that does not return any mailboxes, you might need to call support, as there is something amiss. If you do not see the mailboxes you expect to see, they might be indeed disabled in AD/Exchange, or even hidden from addressbook.
Regards