Hi @tomekm89 the links provided by @xSteveuk covers a lot of the troubleshooting. I would firstly check you have the latest firmware which is 1570.0 released July 2021. If you do not have this it can be downloaded to USB and updated that way. https://www.samsung.com/uk/support/model/UE48JU6000KXXU/
Otherwise Freezing may be sorted via a cold Boot,hold down the power button on the remote until the Tv reboots- should be around 5 seconds. Alternatively unplug from the wall for 30 seconds and try again. However sometimes a Factory Reset is needed which can also solve Network issues. However you may need to reboot Router and best to do this by unplugging from from mains. An other idea is to go to Network Settings- DNS settings. Change from Automatic to 8.8.8.8 or 8.8.4.4 (the Google servers). If still network issue alternative is Open DNS which is 208.67.222.222 or 208.67.220.220 More information on other options here https://www.techradar.com/uk/news/best-dns-server
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 5.1,Android 13 .
