It may be you've reached the 20 forum posts per day maximum post count according to this old official post on forum restrictions (although it was my understanding even you exceeded that count you could still post here in New Player Assistance, Tech Support and Bug Reports).

The post count restriction resets every 24 hours about 5pm Tokyo time as far as I understand it, so you might have to wait another 12 hours or so at least if you have reached that number sadly.