When someone creates an account, signs up for email newsletters and then their email address becomes invalid MKDoc continues to send out email that then bounce back.
There is no way in the admin or superuser interface to know that email is bouncing or to do anything about it other than delete users accounts.
The only way to deal with this at the moment is for the mail servers postmaster to keep track of the accounts that bounce and then to manually disable the sending of emails to these users at a MySQL level.
(TODO: add the MySQL commands needed here)
Stopping the Newsletter Manually
The bounce emails will just have the email address for the user so the first thing to do is to get their ID:
mysql> select ID from Editor where Email="[email protected]"; +----+ | ID | +----+ | 2 | +----+ 1 row in set (0.00 sec)
Then find out which newswltters they have signed up for:
mysql> select * from Preference where Editor_ID="2"; +----+-----------+--------------------+-------+ | ID | Editor_ID | Name | Value | +----+-----------+--------------------+-------+ | 1 | 2 | newsletter-daily | 1 | | 2 | 2 | newsletter-weekly | 1 | | 3 | 2 | newsletter-monthly | 1 | +----+-----------+--------------------+-------+ 3 rows in set (0.01 sec)
Then delete the rows corresponding to this users account:
mysql> delete from Preference where Editor_ID="2"; Query OK, 3 rows affected (0.07 sec)