It appears as though your TV is "loosing" its connection to the hub and it needs to be restarted in order to find it.
You could try getting the TV to use the same IP address each time it connects to the Smarthub.
Log onto the hub and go to the Advance settings and go to My Network. Locate the TV in the list of devices and click on it. When the new page opens scroll down and select "Always use this IP Address" and click Save.
As @gg30340 has already advised, it does sound like the TV is losing it's connection to the hub.
Is it connected by Wi-Fi or ethernet and if by Wi-Fi would it be possible to try a cable instead
I did post some suggestions previously.
Further to the above, it would be better to set a static IP address on the TV itself. I believe the BT hubs start their DHCP pool at 192.168.1.64, so any address below this that isn't used elsewhere would be fine.
That is exactly what it is doing. Only it doesn't always work, I can temporarily fix the fault by doing a "soft reboot" of the tv, after which I can launch any of the various players. It's guaranteed that the next time I switch on the tv and try and launch any of the players it comes up with an error message.
As suggested I've gone into the Hub and located the tv, and saved "YES" against "Always use this IP Address". The connection status is showing "not connected". I tried launching the apps following your advice and got the usual error message.
The fix for this is in preventing the tv loosing its connection to the Hub. How to do this - I wouldn't know.
The fix could well be in connecting the TV to the Hub using an ethernet cable instead of using Wi-Fi. See message 12
Might be worth changing the cable, they don't last forever
The connection is by way of an ethernet cable. I did wonder if there was an issue with the cable, tried a new one, with no resolution of the problem.
It sounds like desperate measures time then, either try another router if you have one or take your TV to a friends house and see what happens
@BillR48wrote:The connection is by way of an ethernet cable. I did wonder if there was an issue with the cable, tried a new one, with no resolution of the problem.
Just an extra thought.
Are you on FTTP and if you are then what is the status of the PON and LOS lights on the Openreach modem (ONT) when the fault occurs