Can watch previews but nothing else. Showing error code vsf:shaka_error_6006
Device/programme?
As mentioned by @redchiz1 could you elaborate the device and content your trying to watch so we can get help you.
What TV is it?
Are you able to delete the app and reinstall?
Tried unplugging the router and TV for a few minutes?
Explain exactly what content you are trying to watch. What membership do you have?