I had this subscription since the 4th issue rolled out. I love it, wrote some questions to the publisher/editor and always got back a thoughtful response. Gave a copy to some friends living on a boat - they love it!
I too had trouble with the "validation error" Dec-Jan - sent a message about my trouble and received a prompt reply TO MY APPLE account. Did as suggested, no problems since.
Jaded Technophile about Tiny House Magazine