Help & troubleshooting for channels on your Roku device, including adding/removing channels, logging in to, authenticating, or activating a channel, channel-specific playback issues, assistance contacting channel publishers to report issues, and adjusting channel-specific settings.
Stations like The Roku Channel, Pluto, etc. don't own most of the programming they carry so they must license their programming from the owners. These licenses cover specified date ranges and specify which geographical regions are covered. The license contracts expire and unless the contract is renewed, the program must be removed.
It sounds like the contract for your show expired at the end of the year.
Roku Streaming Stick +, 3810X, Ser YH0059427035, wifi - Samsung UN55ES6100
Roku Streaming Stick, 3600X, Ser 5S56D8240827, wifi - JVC EM37T
While this is true, Roku usually gives an advance warning when a shoe is disappearing at the end of a month. They gave no warning at all for Without A Trace. I too was on Season Five. I went to watch today, and "poof" it was gone.