If you have not already done so, in the Change Center of the Administration Console, click Lock & Edit (see Use the Change Center).
In the
Administration Console, expand Services and
select Mail Sessions.
The Mail Sessions table displays in the right pane showing all
the mail sessions defined in your domain.
Select one or more mail sessions.
Click
Delete and confirm the deletion.
To activate these changes, in the Change Center of the Administration Console, click Activate Changes. Not all changes take effect immediately—some require a restart (see Use the Change Center).