[Building Sakai] can't view grades in Samigo

[50600822 at stu.hcmut.edu.vn]

Hi,
After created and published an assessment, I loggin as another account to take test and submit it. Then, I logged in again with an maintain account(which I have given any role possible including section.role.instructor, section.role.ta), I can only see the number of submission. When I click on it to view detail, no submission appear in the table. Can somebody tell me how to fix this?
Thanks.