You can keep trying to join in, but your luck may hit yourself when you reach the server!
If you got rejected, a message will be left from Customer Service, stating that you didn’t meet the requirements. Don’t worry, as you can keep applying until you meet them. If you got accepted, you can get a switch button for your account, which can be located in Account Settings, and the Test Server button. Congrats on entering Advanced Server! For iOS users that fit the requirements, you may get an invitation email from Moonton via the in-game email system for active players. The link in the email will direct the user to download. Android users will irregularly get access to Advanced Server with special permits. If a permit is available, you may get the Switch Server button.