There could be a couple of reasons why the interface is not appearing when you set the server id to a number:
1. Check your configuration: Ensure that you have configured the server id correctly in all relevant config files. Double-check for any typos or syntax errors that may be causing the issue.
2. Permissions: Make sure that the user running the server has sufficient permissions to display the login or account creation interface. Check the file permissions and ownership of the files involved.
3. Database configuration: Verify that your database is properly configured and that the server id is correctly set in the database. Ensure that the necessary tables and fields are present for the login and account creation process.
4. Debugging: Enable logging and debug options to get more information about the issue. This can help narrow down the problem and identify any errors or warnings that may be occurring.
If you have tried all the above steps and the issue still persists, consider consulting the documentation or seeking help from the game's developer or community forums for specific troubleshooting steps for your particular game server.