I downloaded about 2 weeks ago and only once played it.I tried from then to enter like 4 times but it says:'Non-preimum can't enter'.So when the heck are the days you can enter?

   And no don't tell me to buy it,I won't.

It might be that the servers are full and the only people who can enter are premium players. You might want to ask their tech support also

In knight online free players are only allowed to play in off-peak hours so you have to play it at another time that is non peak hours.

submit a ticket.