DrBB, the link on cruciverb acted as a proxy and passed the .puz file from the NYT server (which was why one had to be logged in on that site too). Although no links to new .puz files were posted on the NYT Crossword webpage during those 30 or so days, the .puz content was still being put up on their file repository in the usual spot, which was why the cruciverb link still worked during that grace period. Starting very recently the .puz files are no longer being placed on the repository, hence we started and continue to come up dry on the cruciverb link too. Yes, it's frustrating!
DrBB and cwp63, see the subject NY Times Crossword started by Brien (near the top of Support / General Support) for a workaround to continue solving with Across Lite.