If the transfer stops in the middle of your transfer this can be for a number of reasons.
Check your internet connection has not dropped.
Is your network busy?
Is there a bandwidth restriction in place on your companies network?
If there is a problem with our servers, you would be presented with a MailBigFile branded page notifying you of the fact.
Uploads are not resumable, so unfortunately in most cases you will need to restart you transfer by going back to the homepage.