I have not heard of this happening before, however there are a few things you can try:
- Make sure you're logged in as the correct user (some people have multiple logins or a shared login for scheduled reports)
- Check the Data Warehouse sent history to see if prior schedules have been working correctly
If you're still unable to determine the root cause of the issue, you can have a Customer support delegate contact Customer Care so further troubleshooting can be done.