Hi @HackerHoare Check that all your cables are securely connected and there is no issue there. If fine there I would suggests disconnecting all cables and switching off the mains for around 10 minutes. Afterwards reconnect ,at this point see if you are able to check the firmware on the Tv as an update may be available. You have not named the model but can check on the Samsung support site and download to USB if applicable. https://www.samsung.com/uk/support/ Regardless also an idea to Factory Reset if possible.
I do not work for Samsung or make Samsung Products but provide independent advice and valuable contributions.
My Device- S21 Ultra 5G ( SM-998B/DS ) CSC= BTU , 12GB/256GB One Ui 5.0,Android 13 .