Slot booking fails

I am trying to book a VAC slot @ Mumbai in September for H1B visa interview. I am currently in US.
I can view the slots, select a slot and submit. Don't get any confirmation and the page goes back to the consular location selection page. Sam results when I tried from 3 different browsers, 2 PCs, with and without VPN, with and without incognito over multiple days.

Tech support hasn't been helpful. Has anyone been able to get past this problem?