OK, this is a new one to me. I'm running CiviCRM 4.6.6 on WordPress 4.3. For the individual contacts I added manually, CiviMail works awesome. But here's where things get weird.
I just finished importing a list of contacts into a new group (not a big list, just 104, that were exported from a previous CiviCRM install). I made sure to select only basic fields to import. Imported them into a new group. Import seemed to go fine. Changed the group setting to Mailing List.
But then when I tried to use CiviMail to send a mail to that group, CiviMail says "No Recipients."
So I added an previously entered contact into the new group, and when I tried CiviMail again, it says "1 recipient" (even though there are 101 showing up in the group).