Incoming Emails do not create or update tickets on Service Desk Manager and they are stored under \site\mail_unknown folder.
Why are they stored in the mail_unknown folder?
An incoming email is filtered by Mailbox Rules.
If 'Save Unknown Emails' option is set to "Yes" on a Mailbox setting, and the email is not processed due to the following, it will be stored in (Service Desk)/site/mail_unknown folder.
* The email does not meet the defined Mailbox rules.
* The email has a wrong format or character set.
* You set 'Action' to "Ignore email" or "Ignore email and Reply" in the Mailbox Rule and the email meets the Rule.
* Also, if the option 'Allow Anonymous' is not checked on the Mailbox setting and the email is sent out from a contact with an email address that does not exist in Service Desk Manager, it will be moved to the mail_unknown folder too.
Use the Default Mailbox or Create a Mailbox:
Fixed Issues - 14.1.03
Title: SAVING EMAILS FROM UNKNOWN SENDERS
TEC1865658: How to add a mailbox rule that matches all incoming emails
TEC1945266: How to enable incoming emails update tickets, though the email address is not in SDM repository?