Symptoms
No emails (client events or email events) are sending. The error in the log is "Mailbox has exceeded maximum mailbox size."
Diagnoses
The mailbox for the K2 email account is full.
Resolution
Unless you are saving the emails for audit purposes, it is safe to clear out the mailbox. In fact, we do suggest cleaning out the mailbox regularly (http://help.k2.com/onlinehelp/K2blackpearl/ICG/current/webframe.html_SmartActions_fail_mailbox_full.html). With fixes implemented in 4.6.9, it is safe to use a retention policy to do this automatically. After clearing out the mailbox, restart the K2 service to make sure it picks up the changes.
