Train tickets for November

Hello - I will be in UZ from November 22-29. I tried to buy tickets for the train for the 24th and 25th, and the high speed trains appeared 2 days ago, but now are gone saying there are no spots left. Can this be true that they are sold out 55 days from now, or will they reappear later.

Is there another reputable website to buy these tickets through other than the official website?