Oh, actually yesterday when it happened, I stop trying for few hours before trying again but the situation didn't change. Really no idea what is the cause as I didn't do anything but just submit a ticket through mobile app, after a while it suddenly work again. Not sure why only happened to me.
Their customer service replied but told me to check my phone notification setting which obviously not the cause as I didn't change anything and it suddenly work again.
As I also told them I use the manual authenticate which also failed, they gave me a link to tell me to see if I did it wrongly. I was hoping they could at least retrieve some logs to reveal some insights on why the manual login failed.
So surprised with their replies which are like them not knowing anything and guessing what may be the cause. But so far their CS are not very useful. A couple of times waited for a week or two to receive some replies that don't answer the questions. Lucky there is this forum to seek help

from many experts.