"Title and author certification" needs to be confirmed twice

[fripSide]

Every time I submit, the server tells me that the "Title and Author Certification" option [1] is unchecked and asks me to submit again with it checked. But I definitely checked it.

So I have to submit twice for a single change, and all the authors get two email notifications.

How to correctly check the "Title and Author Certification" option [1] during submition ? This item is checked in may pages but server still regard it as unchecked after I click "save and submit".

Do I need to refresh the page before a submition?

[1] We certify that the title, author list, and abstract exactly match those in the final PDF.