Hi Jianlong,
Sorry you have this problem.
There are a number of things you can try to troubleshoot this issue.
Please can you take a look at this link which has a number of steps to resolve the issue - http://help.videoscribe.co/support/solutions/articles/1000033700
If following the advice on the link does not resolve the issue, please can you use this link to raise a support ticket detailing what you have tried already.
Here is the direct
link to log a ticket
http://help.videoscribe.co/support/tickets/new
Thanks, Joe
Jianlong Zou