Why can't I log in to the online class and say that I have logged in many times?

Generally speaking, it's because you didn't click automatic login. Sometimes you will be asked to log in again in class, just because the background is unstable or the network is unstable. There is also the need to log in to the subject's account again because the subject's nailed account has been logged in by others, or it may be that the subject's mobile phone signal is not good, resulting in disconnection.