I have never experienced this, you may wish to email support here for a faster reply:
Hi Hong Yu,
Thank you for reporting this to us.
I have made some changes to your account. Please can you re-install the AppUp(SM) Center and try to log-in again?
Intel® Customer Support
Intel® Atom™ Developer Program
Intel® AppUp(SM) Center
Were you able to resolve the issue with your account?
Please could you provide us with your username (email address) and I will do the necessary.
For privacy you can send us this information via email to firstname.lastname@example.org
Intel AppUp(SM) Center
Intel AppUp(SM) Developer Program
yes. it has been all right since Monday. Thank you.
I think I should try not to re-install appup client ASAP to avoid that might happen again.