1,1under the age of 8: According to the regulations for preventing minors from indulging in games,1under the age of 8 cannot use the game account, so it is impossible to set a birthday.

2. Birthday has been set: If a birthday has been set before, you cannot change the birthday information again.

3. Account number problem: the account number is abnormal or blocked, and the birthday cannot be set.

4. Game version problem: The old version of the game will not be able to access the latest functions and options. Try updating the game to solve the problem.

5. Server maintenance: If the game server is under maintenance, some functions will be affected. Please wait a moment, and then try to set your birthday again.