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.
Try removing the channel from the Roku home screen by navigating to the channel tile, pressing the * key on your remote and choosing 'Remove channel'. Then restart your device from Settings>System>System restart. Once your player starts up again, add the channel back once more.
Uninstalling and reinstalling the app doesn't fix it. It's been like this for months. I contacted TBS/TNT about it and they were no help either. Not sure whose issue it is but it makes the channels unwatchable.
Make sure that when removing the channel, that you restart the device before adding the channel back again.
If the issue remains unresolved, I'd recommend reaching out to TBS support directly to report the issue and request additional support. Many channels on the Roku platform are developed and maintained by the channel provider directly, and they'll be able to best assist. If other channels are working correctly, and you only experience this issue on the TBS channel (app), that is likely an indication that the issue lies within that particular channel. In these cases, the channel provider will need to investigate the issue in order to help resolve it.
I've been watching TBS via Roku for years. It only stopped working the past week or so. I followed your steps of removing TBS from the Roku home screen by navigating to the TBS channel tile, pressing the * key on the remote and choosing 'Remove channel'. Then I restarted the Roku device by going to Settings>System>System restart. Then I readded TBS. I still get the same error "Sorry, but we were unable to authenticate your device and can't continue". I've checked for Roku system updates, but there weren't any. It doesn't seem to be the device. I can get onto Netflix, FOX, and Comedy Central no problem, just to name a few, the latter two authenticating via my cable provider as TBS should. Please help. Roku is pointing fingers at TBS and TBS is pointing fingers at Roku from the reading I've done. I think the 2 companies might need to work together. Thanks.