Problems with Interspire email program. Need Fix for (Invalid Login Details for Bounce Processing) Error

We are using InterSpire email program which (LACKS ANY REAL SUPPORT) so we are seeking someone who understands how to correct a consistent error we receive regarding bounce processing. Every time we do a mailing we receive the following message: (Invalid Login Details for Bounce Processing) Automatic bounce processing was trying to log in to the email account (username 'bad_address@[login to view URL]' at the email server '[login to view URL]') but was unable to. It received the following error message: 'No such host as [login to view URL]'. Log in to the Control Panel here: http://xxxxx-xxxs/admin/[login to view URL] Edit the contact list here: http://xxxxx-xxxs/admin/[login to view URL] Page=Lists&Action=Edit&id=1 Then check the username, password and mail server details and options are correct. You may need to use the 'Extra Mail Settings' options to fix the error.