Errors on Samsung Smart TV

I`m working out with FB Plus on a Samsung Smart TV. For a few weeks now, the TV has been unable to load my calender or anything else under the "My fitness"-Button (saying "Unable to load calendar" or "Uh oh, something went wrong"). The only thing accessible is my dashboard, and I can go to my scheduled workouts that way. When I play the videos, they show an error, but play anyway. I can not mark them as completed, though, so I do that on my laptop instead (everything works on there).

I`m sure the TV is to blame, because I`ve had similar trouble before. I didn`t do anything then, it just went back to normal on its own. Can anyone give me any advice about what I could do? Refreshing doesn`t help at all. I could just use my laptop to work out, but prefer the big screen of the TV...

Thanks a lot!

Edited