The logshipping job actually works as following :
- Create log or other type of backup from source database .
- Select backup , include backups created in backup job or previouse log shipping job that not shipped.
- Restore backups to target database.
That is , even this time it fails (in backup or restore stage ), when it next runs , it will continue from last failure time point, and it can select backup or logs necessary automatidally to restore to target database.
After it fails , all you need to do is to find and resolve the issue that causes the failure , and wait it next time to run if it is scheduled , you can also run it manually.