They are restricting server loads due to the Duty Finder messing up because of the large amounts of player from cross servers trying to access it. Once they have more Duty Finder servers, they will lift the restrictions. I don't know if you remember the first few days of Head Start, but there was no issue actually getting into the game. The problem was with getting into instances. Sadly, this game requires a lot of people to access Duty Finder at any given moment, therefore, gameplay was seriously hindered. They had two choices, having everyone basically stuck in their character progression and fate grind all day,.. or put a heavy restriction so that the ones that can play may progress. The choice they made was obvious.