We recommend that instead of E-txt Desktop you use our SaaS application, Message Manager. Simply login to our User Portal and select Applications - Message Manager.
E-txt allows you to automatically opt-out contacts that have a specific receipt status. For example, if a message to a certain contact is rejected 3 times, then you can opt-out that contact from group.
To access the auto-opt out menu, go to Tools> Automatic Opt-Out Criteria. Simply select which status to monitor, and the number of occurrences