Anna University — Online exam login issues

I faced too many issues during my online exams like the circle turns red even if I turn on the fan, I was not able to complete my discrete mathematics exam around last 20 mins because of login issues, I called the helpdesk and they said try to log in after 3mins, I've tried it also but the time went to last 10mins, the helpdesk said students cannot login on the last 10 mins
Because of these issues I got arrear on my discrete mathematics exam
I kindly request you, I want to take a re-exam in discrete mathematics