Vanilla free realm transfer closed?

i transferred my lv60 priest from faerlina to whitemane for free one month ago, everything went well.
now i want to free transfer my lv60 mage but target server list is empty
but with paid transfer i can see bunch of server names in the list, and whitemane is one of them.
is free realm transfer closed for vanilla wow? if i cant transfer my mage im gonna have to stop subscription now.