Hi @Clarehearing Sorry you are having a problem with some of your subscription channels.
Check out On Demand freezing and poor quality picture for some checks you can complete.
If this does not help resolve the issue can you confirm you are connected from the hub to the youview box via ethernet cable or if you are using powerline adapters? Also have you been able to watch these channels before and the fault has only started recently? Post back and let me know.
Cheers
John