There are several possible reasons why the download button may not be showing on Netflix. It could be due to an issue with your device or with the Netflix app itself. It could also be because the title you're trying to download may not be available for download or may have expired the download window. Another reason could be that you may not have enough storage space on your device to download the title. As a first step, it's always a good idea to check if your Netflix app is up-to-date and if there are any pending software updates for your device. If the issue persists, you may want to contact Netflix support for assistance.