Disable Undeliverable Recipients dialog
This dialog lets you disable failed recipients. You can then delete the disabled recipients by selecting Recipients->Remove Disabled from the main menu.
Only permanently undeliverable recipients Disable only the recipients who are marked as permanently undeliverable. It is very unlikely that these recipients will work again.
Also ones failed temporarily at least: Disable not only permanently undeliverables but some of them who failed temporarily. You need to select the number of times the recipient must have failed to be disabled.
All undeliverable recipients Disable all undeliverable recipients. We do not recommend using this option, especially if you send direct.