You're likely hitting the 10mb cap on files:
File Storage
Hosting accounts may not be used to store backups, personal files, or non-web accessible files. Any files hosted on the account must be directly related to the website the account is intended for. Files over 10MB in size will be automatically removed from non-upgraded accounts.
Until the Prime/Illuminated options return, the best advice I can give would be to host the video on Youtube or another similar video host.