2FA authenticator doesn't work - error with pressing the pound key

Question

Hi,

I was trying to get into my school's system using the 2FA Authentication from China. It required to press the pound key after receiving the phone call as usual. However, this time, after I pressed the pound key on my phone, the phone call just hung up and I failed to log in. It said "We called your phone but didn't receive the expected response. Please try again." How can I solve this problem? I have a bunch things to deal with right now and I am really anxious.