Since server merge, I have exactly 52 characters on Dart Malgus server.
Game Update 5.5.1 Patch Notes say, among other: "The maximum amount of character slots a player can have via paid slot unlocks has been increased to 100 (up from 52)"
I cannot create new characters, because I "have reached the limit for Activated Characters and cannot create aditional characters". I bought and used Cartel Market item "Server Character Slot", but still I cannot create a new character.