1. If you are really just late, you can contact the teacher and provide evidence that you are just late but not absent from class, such as speech records and live broadcast records. After verifying the situation, the teacher will make up the sign. Most online course platforms provide sign-in function.
2. Wait for the second check-in. Many teachers will sign in several times in a class, such as signing out. Waiting for the second time can also prove your attendance.
If you are really absent from class, then accept the ending. Occasionally absent from class has little effect on grades, as long as there is no shortage in the future.