If you are resuming a mailing which you previously stopped, make sure you have saved your project. The Start button will turn to Resume when you reopen the project. Note, the recipients of the project should not be changed before you resuming the mailings.
Generally, Email Marketer will try to resend the failures automatically unless you click the Stop button.
To resend the failures manually, at the Publish tab, please:
1. If the Resume button is enabled, just click it to resend the failures;
2. If the Resume button is disabled, please click the button Options and Performances and add the retries, click Resume;
3. To resend a single failure message, please click Failure Details and double click the failure item. Click the button Send This Message at the new dialog.