Related Error Message
Connection failed because the server reached its maximum amount of clients.
This error is because the number of connected users equals the maximum number of users purchased. Try to reconnect, however if this error persists the user count of the server may need to be upgraded. You can do this by following this article:
Reserved Slots
Creating a few reserved slots will allow you and your admins to enter the server even when it is "Full" that way you always have some sort of access. If this continually happens you should probably get a larger server. You can do this by upgrading your server here: https://tserverhq.com/clients/clientarea.php?action=products
Upgrade Server
The best option would to upgrade your server to a larger size. Doing this at any time is acceptable and instantly takes effect.