Quote Originally Posted by EorzeaWanderer View Post
This actually won't work for world servers that are designated as "Congested" worlds. It is not possible to create characters on those worlds at any time, until SE actively removes the "Congested" designation.

Other worlds might temporarily step in and out of the "Creation of New Characters Unavailable" status, because that status is dynamically assigned and removed based on live login counts. In this case, the above advice (creating a character in off-peak hours) will work.

If a world is marked as "Congested", however, it is blocked from all new characters until SE decides to reverse the decision, which is usually re-evaluted and applied in the next patch.
For years Balmung was designated as Congested. However, around 4am you could create a new character. Congestion is based on currently logged in characters. If your server is so busy that at all times there is a number of players logged in, then yes you can never create a character. However, the congested tag does disappear if the number of people logged in is below the predetermined log in amount. Best place to watch if it opens is https://arrstatus.com/
it auto refreshes and will let you use notifications when a server opens up.