If your computer crashed during the upload, or Lightroom crashed, you will need to start over.
To start over, all you need to do is create a new job submission, and add your same images to that submission:
Right Click on the plug-in on the left side
Go to "Create Job" to create a new job
Move your images into the new job
Hit Publish to start the upload again
* Refer to Upload a job page for the tutorial video.
This upload should go much faster, as Lightroom has already created all of the smart previews for your images, and just needs to package it up and upload it.
Please do feel free to write to us at MyLifeBack@ShootDotEdit.com for any further assistance, questions or queries.