Dear Joyce, 

July 8 was the last date to register/make payment for second round of AIQ, it could be the reason for the server error, as the number of students filling or registering is always very high. I hope your issue got resolved. 

For future reference, if it happens, you could try using different browser, like if chrome isnt working, then try IE or Mozilla, etc. Or try some time later. 

Good Luck!