If you don't graduate completely, you can enter (if you graduate from a certain subject, you won't automatically quit). Since you quit automatically, you must have graduated completely. But if you have a level above 30, you can't enter automatically. At this time, you can still manually enter any tutor's office, provided that the number of people in the chat room is less than 50. If the chat room is full of 50 people, people who have not graduated from level 30 or above can't get in.