I use WooCommerce in conjunction with the Amazon S3 for Woocommerce plugin to sell digital downloads and until yesterday it worked great. Now when clicking on the download link after purchase, the user gets a "Invalid Download" message. Anyone know how to fix this? I've googled it to death, reinstalled both Woocommerce and the S3 plugins, check and re-checked settings ... to no avail. This is my busiest sales season and I desperately need this to work. Any help would be greatly appreciated.