BCC emails not working - is there a log I can view?
The Administer Screen Settings - Outbound Mail gives you the option to enable Redirect to Database. (You can navigate to the screen with Administer -> System Settings -> Outbound Email (SMTP/SendMail), or with civicrm/admin/setting/smtp?reset=1)The mail is spooled to the table civicrm_mailing_spool.

Update: In case of the use of cc: and bcc: it is a bit tricky. I just did a short search in the code and found that, when the Pear mailing library is installed, the bcc and the cc: are removed from the Headers and added to the list of recipients. CRM-19173 explains the reason. So in the spool table, they can be found in the recipient_email appended to the list of email addresses, but not in the headers.

See the code at Mail.php line 260.