Someone has to send you one, and members can only unlock them with bonus points (you used to get a certain number for free, but they stopped doing that and took away all the unused invites not too long ago). Maybe someone nice with lots of extra bonus points will see your thread here and send you one :) I don't have that many bonus points at the moment.
I think the last time Avistaz had open registration was a couple months ago. just keep an eye on the site --- they do open up every now and then. AOX is another tracker, although it's relatively new and still building a community (so its library is smaller), but it has open registration right now until September 20th November 1st.
Keep an eye on THIS reddit, they post when registration is open. If you are looking for a good place to watch dramas in the mean time I rly recommend ViewAsian ive been using this site instead of kissasian for months now, it's so much better.