Hi
@haslo Helps to name the model.
However check the certified Devices here
https://www.bbc.co.uk/iplayer/help/questions/supported-devices/samsungis there is any difference between the standard and Beta version of iplayer?
Ensure the Tv and app are on the latest updates, iplayer may be set to Auto update though. You could try reinstalling the app to see if that helps, an idea also to try a soft Reboot by holding in the power button for around 5 seconds until the Tv reboots as this clears the cache.
You may though need to switch the Tv off at the mains and reboot your router simultaneously for around 30 seconds before trying again. A Factory reset is sometimes necessary mind you.
If you have been in touch with iplayer to no avail know though of ocasssions when there has been an issue at Samsung's end and you could contact support if it remains unresolved.
https://www.samsung.com/uk/support/