I’ve been using this 4-channel unit since mid-2017. I do not have a subscription. I have set manual recurring timers to record, for example, some of the late shows (since I can’t stay up that late in my old age 
) on weeknights.
Suddenly in January 2020 this no longer works. But here is the MYSTERY: If I create a non-recurring timer off the live grid, next day I find it has worked. If I do the exact same thing but select multiple days, it doesn’t work.
Of course I rebooted with the button and I rebooted by powering off for 15 seconds. I deleted all the timers and created new ones. The disk is a 1 TB WD Elements and has 811 GB available. No changes to my network infrastructure.