Mail handler configuration:
SECURE POP
Port: 995

Email message of the user who has wrong permission to service desk (for example doesn't have "Customer" permission) is deleted without any notification ( neither as an email to Project Administrator nor exception in JIRA log). In standard JIRA mail handlers configuration we have field for email address which is used to forward unprocessed emails. Here should be the same solution.

We can find more if we turn Incoming Mail debugging on. Then we can see for example:

2014-12-12 10:16:41,750 atlassian-scheduler-quartz1.clustered_Worker-4 DEBUG anonymous    Mail handler used by JIRA Service Desk. Do not modify or delete. 10,113 [atlassian.mail.incoming.sd] The message has been rejected (The Service Desk you are trying to view does not exist.): From :[Robert Zube <r.zube@adbglobal.com>], Subject: Question10, Date:

From this log we can retrieve another bug because JIRA says that Service Desk is not exist but it is not true .