Well, messing around with sro packets I discovered the following:
At first, sro server send u a packet [FF1], once you login, you receive a [FF2] packet, and, if the server is full, you keep getting [FF3].
It is suppossed that once there's room enough, and its your turn, you receive you characters data.
However, sometimes, when its your turn you just receive:
[FF1] and [FF2] (again), and you do not longer receive any missatges.
If that happens you won't log in, and even sometimes it will be imposible for you to click the [Exit] button.
So, when that happens, the best you can do is: restart sro.
At least that was my experience.