@pinkstonm check you have the latest firmware, though it is a 2016 model.
A few additional things to try, hold the power Button for around 5 seconds until the Samsung logo displays and the Tv is restarted. check the streaming and if that does not work unplug the Tv for 5 minutes. with regards to wifi You could also change the channel on your router and possibly split the 2.4 and 5 Ghz as shown here https://support.accessagility.com/hc/should-i-use-different-ssids-for-2.4-ghz-and-5-ghz-bands-on-sam...
Sometimes it is necessary to change the DNS Settings,Go to Network-Network Settings-DNS Settings. Change from Automatic to to 8.8.8.8 or 8.8.4.4 (Google servers) An alternative is Open DNS 208.67.222.222 or 208.67.220.220
could also try a Factory Reset if mot attrmpted already.
I do not work for Samsung or make Samsung Products but provide independent advice and valuable contributions.
