To enable OTRS to send emails you need at least a valid email address used by the system. Because many setups need more than one mail addresses OTRS is able to work with many mail addresses at the same time. At least one mail address can be specified for a queue, but it is also possible to specify the same address for more than one queue. That means that more than one address can be used to send mails from outsite to a queue, but one address has to be specified for the outgoing mails of a queue. The address, that shall be used for outgoing messages of a queue, can be set if the queue is created. Follow the "Email Addresses" link to manage all mal addresses of the system.
If you create a new mail address you can select the queue or sub queue that shall be linked with the new address. This link enables the system to sort incomming messages via the address in the To: field of the mail into the right queue.
To keep the consistency of the data for OTRS it is not possible to delete a mail address. To deactivate a mail address set it to "invalid" or "invalid-temporarily".