Thanks for your help~
To solve the problem, please kindly check the following details:
1. Please make sure the time/date on your computer is the same with the local time/date.
2. Please make sure you do not set LAN/proxy in your Internet Explorer nor using proxy service.
3. Please kindly check whether you could visit https://u1.sothink.com/
using your IE or not(you will see the words "Welcome to Sothink Test Server" if you could visit the above site successfully).
If you could not see the words, please kindly tell us the error appears.
4. Please deactivate your firewall and then register the program for a try.
If the above still does not help, please provide us with the detailed information of your Operating System for further checking.
If you need further assistance please kindly write to firstname.lastname@example.org
Have a nice day!