My 1TB passport doesn’t appear to be working. On my apple app, the recording function is absent. It used to be there when you click on a show, but now its missing.
If it’s indeed your HD, Try another player/playback device such as laptop/desktop/Roku/iPhone/Firestick/etc. and see if that function is available… If it is, do several recordings first and play it to make sure it’s definitely working… Maybe it’s the Apple TV App need bug fix?? If not, get another working HD to replace it… Goodluck…
Are you recording other things and out of tuners?
Does your Tablo have a subscription? Any chance your 30-day trial ran out? Here’s a breakdown of how the Tablo works with and without a subscription: https://www.tablotv.com/tablo-products/tablo-guide-data-subscription/